dsphinx.addnodesdocument)}( rawsourcechildren]( translations LanguagesNode)}(hhh](h pending_xref)}(hhh]docutils.nodesTextChinese (Simplified)}parenthsba attributes}(ids]classes]names]dupnames]backrefs] refdomainstdreftypedoc reftarget(/translations/zh_CN/cdrom/cdrom-standardmodnameN classnameN refexplicitutagnamehhh ubh)}(hhh]hChinese (Traditional)}hh2sbah}(h]h ]h"]h$]h&] refdomainh)reftypeh+ reftarget(/translations/zh_TW/cdrom/cdrom-standardmodnameN classnameN refexplicituh1hhh ubh)}(hhh]hItalian}hhFsbah}(h]h ]h"]h$]h&] refdomainh)reftypeh+ reftarget(/translations/it_IT/cdrom/cdrom-standardmodnameN classnameN refexplicituh1hhh ubh)}(hhh]hJapanese}hhZsbah}(h]h ]h"]h$]h&] refdomainh)reftypeh+ reftarget(/translations/ja_JP/cdrom/cdrom-standardmodnameN classnameN refexplicituh1hhh ubh)}(hhh]hKorean}hhnsbah}(h]h ]h"]h$]h&] refdomainh)reftypeh+ reftarget(/translations/ko_KR/cdrom/cdrom-standardmodnameN classnameN refexplicituh1hhh ubh)}(hhh]hSpanish}hhsbah}(h]h ]h"]h$]h&] refdomainh)reftypeh+ reftarget(/translations/sp_SP/cdrom/cdrom-standardmodnameN classnameN refexplicituh1hhh ubeh}(h]h ]h"]h$]h&]current_languageEnglishuh1h hh _documenthsourceNlineNubhsection)}(hhh](htitle)}(hA Linux CD-ROM standardh]hA Linux CD-ROM standard}(hhhhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhhhB/var/lib/git/docbuild/linux/Documentation/cdrom/cdrom-standard.rsthKubh field_list)}(hhh](hfield)}(hhh](h field_name)}(hAuthorh]hAuthor}(hhhhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhhhKubh field_body)}(h-David van Leeuwen h]h paragraph)}(hhh](hDavid van Leeuwen <}(hhhhhNhNubh reference)}(hdavid@ElseWare.cistron.nlh]hdavid@ElseWare.cistron.nl}(hhhhhNhNubah}(h]h ]h"]h$]h&]refuri mailto:david@ElseWare.cistron.nluh1hhhubh>}(hhhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhKhhubah}(h]h ]h"]h$]h&]uh1hhhubeh}(h]h ]h"]h$]h&]uh1hhhhKhhhhubh)}(hhh](h)}(hDateh]hDate}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1hhjhhhKubh)}(h 12 March 1999h]h)}(hjh]h 12 March 1999}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhKhjubah}(h]h ]h"]h$]h&]uh1hhjubeh}(h]h ]h"]h$]h&]uh1hhhhKhhhhubh)}(hhh](h)}(h Updated byh]h Updated by}(hj9hhhNhNubah}(h]h ]h"]h$]h&]uh1hhj6hhhKubh)}(h#Erik Andersen (andersee@debian.org)h]h)}(hjIh](hErik Andersen (}(hjKhhhNhNubh)}(handersee@debian.orgh]handersee@debian.org}(hjRhhhNhNubah}(h]h ]h"]h$]h&]refurimailto:andersee@debian.orguh1hhjKubh)}(hjKhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhKhjGubah}(h]h ]h"]h$]h&]uh1hhj6ubeh}(h]h ]h"]h$]h&]uh1hhhhKhhhhubh)}(hhh](h)}(h Updated byh]h Updated by}(hj{hhhNhNubah}(h]h ]h"]h$]h&]uh1hhjxhhhKubh)}(hJens Axboe (axboe@image.dk) h]h)}(hJens Axboe (axboe@image.dk)h](h Jens Axboe (}(hjhhhNhNubh)}(haxboe@image.dkh]haxboe@image.dk}(hjhhhNhNubah}(h]h ]h"]h$]h&]refurimailto:axboe@image.dkuh1hhjubh)}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhKhjubah}(h]h ]h"]h$]h&]uh1hhjxubeh}(h]h ]h"]h$]h&]uh1hhhhKhhhhubeh}(h]h ]h"]h$]h&]uh1hhhhhhhhKubh)}(hhh](h)}(h Introductionh]h Introduction}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjhhhhhK ubh)}(hLinux is probably the Unix-like operating system that supports the widest variety of hardware devices. The reasons for this are presumablyh]hLinux is probably the Unix-like operating system that supports the widest variety of hardware devices. The reasons for this are presumably}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhKhjhhubh bullet_list)}(hhh](h list_item)}(h~The large list of hardware devices available for the many platforms that Linux now supports (i.e., i386-PCs, Sparc Suns, etc.)h]h)}(h~The large list of hardware devices available for the many platforms that Linux now supports (i.e., i386-PCs, Sparc Suns, etc.)h]h~The large list of hardware devices available for the many platforms that Linux now supports (i.e., i386-PCs, Sparc Suns, etc.)}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhKhjubah}(h]h ]h"]h$]h&]uh1jhjhhhhhNubj)}(hXThe open design of the operating system, such that anybody can write a driver for Linux.h]h)}(hXThe open design of the operating system, such that anybody can write a driver for Linux.h]hXThe open design of the operating system, such that anybody can write a driver for Linux.}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhKhjubah}(h]h ]h"]h$]h&]uh1jhjhhhhhNubj)}(hLThere is plenty of source code around as examples of how to write a driver. h]h)}(hKThere is plenty of source code around as examples of how to write a driver.h]hKThere is plenty of source code around as examples of how to write a driver.}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhKhjubah}(h]h ]h"]h$]h&]uh1jhjhhhhhNubeh}(h]h ]h"]h$]h&]bullet-uh1jhhhKhjhhubh)}(hX*The openness of Linux, and the many different types of available hardware has allowed Linux to support many different hardware devices. Unfortunately, the very openness that has allowed Linux to support all these different devices has also allowed the behavior of each device driver to differ significantly from one device to another. This divergence of behavior has been very significant for CD-ROM devices; the way a particular drive reacts to a `standard` *ioctl()* call varies greatly from one device driver to another. To avoid making their drivers totally inconsistent, the writers of Linux CD-ROM drivers generally created new device drivers by understanding, copying, and then changing an existing one. Unfortunately, this practice did not maintain uniform behavior across all the Linux CD-ROM drivers.h](hXThe openness of Linux, and the many different types of available hardware has allowed Linux to support many different hardware devices. Unfortunately, the very openness that has allowed Linux to support all these different devices has also allowed the behavior of each device driver to differ significantly from one device to another. This divergence of behavior has been very significant for CD-ROM devices; the way a particular drive reacts to a }(hj7hhhNhNubhtitle_reference)}(h `standard`h]hstandard}(hjAhhhNhNubah}(h]h ]h"]h$]h&]uh1j?hj7ubh }(hj7hhhNhNubhemphasis)}(h *ioctl()*h]hioctl()}(hjUhhhNhNubah}(h]h ]h"]h$]h&]uh1jShj7ubhXV call varies greatly from one device driver to another. To avoid making their drivers totally inconsistent, the writers of Linux CD-ROM drivers generally created new device drivers by understanding, copying, and then changing an existing one. Unfortunately, this practice did not maintain uniform behavior across all the Linux CD-ROM drivers.}(hj7hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhKhjhhubh)}(hXThis document describes an effort to establish Uniform behavior across all the different CD-ROM device drivers for Linux. This document also defines the various *ioctl()'s*, and how the low-level CD-ROM device drivers should implement them. Currently (as of the Linux 2.1.\ *x* development kernels) several low-level CD-ROM device drivers, including both IDE/ATAPI and SCSI, now use this Uniform interface.h](hThis document describes an effort to establish Uniform behavior across all the different CD-ROM device drivers for Linux. This document also defines the various }(hjmhhhNhNubjT)}(h *ioctl()'s*h]h ioctl()’s}(hjuhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjmubhf, and how the low-level CD-ROM device drivers should implement them. Currently (as of the Linux 2.1. }(hjmhhhNhNubjT)}(h*x*h]hx}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjmubh development kernels) several low-level CD-ROM device drivers, including both IDE/ATAPI and SCSI, now use this Uniform interface.}(hjmhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhK%hjhhubh)}(hXAWhen the CD-ROM was developed, the interface between the CD-ROM drive and the computer was not specified in the standards. As a result, many different CD-ROM interfaces were developed. Some of them had their own proprietary design (Sony, Mitsumi, Panasonic, Philips), other manufacturers adopted an existing electrical interface and changed the functionality (CreativeLabs/SoundBlaster, Teac, Funai) or simply adapted their drives to one or more of the already existing electrical interfaces (Aztech, Sanyo, Funai, Vertos, Longshine, Optics Storage and most of the `NoName` manufacturers). In cases where a new drive really brought its own interface or used its own command set and flow control scheme, either a separate driver had to be written, or an existing driver had to be enhanced. History has delivered us CD-ROM support for many of these different interfaces. Nowadays, almost all new CD-ROM drives are either IDE/ATAPI or SCSI, and it is very unlikely that any manufacturer will create a new interface. Even finding drives for the old proprietary interfaces is getting difficult.h](hX5When the CD-ROM was developed, the interface between the CD-ROM drive and the computer was not specified in the standards. As a result, many different CD-ROM interfaces were developed. Some of them had their own proprietary design (Sony, Mitsumi, Panasonic, Philips), other manufacturers adopted an existing electrical interface and changed the functionality (CreativeLabs/SoundBlaster, Teac, Funai) or simply adapted their drives to one or more of the already existing electrical interfaces (Aztech, Sanyo, Funai, Vertos, Longshine, Optics Storage and most of the }(hjhhhNhNubj@)}(h`NoName`h]hNoName}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1j?hjubhX manufacturers). In cases where a new drive really brought its own interface or used its own command set and flow control scheme, either a separate driver had to be written, or an existing driver had to be enhanced. History has delivered us CD-ROM support for many of these different interfaces. Nowadays, almost all new CD-ROM drives are either IDE/ATAPI or SCSI, and it is very unlikely that any manufacturer will create a new interface. Even finding drives for the old proprietary interfaces is getting difficult.}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhK,hjhhubh)}(hXRWhen (in the 1.3.70's) I looked at the existing software interface, which was expressed through `cdrom.h`, it appeared to be a rather wild set of commands and data formats [#f1]_. It seemed that many features of the software interface had been added to accommodate the capabilities of a particular drive, in an *ad hoc* manner. More importantly, it appeared that the behavior of the `standard` commands was different for most of the different drivers: e. g., some drivers close the tray if an *open()* call occurs when the tray is open, while others do not. Some drivers lock the door upon opening the device, to prevent an incoherent file system, but others don't, to allow software ejection. Undoubtedly, the capabilities of the different drives vary, but even when two drives have the same capability their drivers' behavior was usually different.h](hbWhen (in the 1.3.70’s) I looked at the existing software interface, which was expressed through }(hjhhhNhNubj@)}(h `cdrom.h`h]hcdrom.h}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1j?hjubhC, it appeared to be a rather wild set of commands and data formats }(hjhhhNhNubhfootnote_reference)}(h[#f1]_h]h1}(hjhhhNhNubah}(h]id1ah ]h"]h$]h&]autoKrefidf1docnamecdrom/cdrom-standarduh1jhjresolvedKubh. It seemed that many features of the software interface had been added to accommodate the capabilities of a particular drive, in an }(hjhhhNhNubjT)}(h*ad hoc*h]had hoc}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubh@ manner. More importantly, it appeared that the behavior of the }(hjhhhNhNubj@)}(h `standard`h]hstandard}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1j?hjubhd commands was different for most of the different drivers: e. g., some drivers close the tray if an }(hjhhhNhNubjT)}(h*open()*h]hopen()}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubhXa call occurs when the tray is open, while others do not. Some drivers lock the door upon opening the device, to prevent an incoherent file system, but others don’t, to allow software ejection. Undoubtedly, the capabilities of the different drives vary, but even when two drives have the same capability their drivers’ behavior was usually different.}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhK=hjhhubhfootnote)}(hI cannot recollect what kernel version I looked at, then, presumably 1.2.13 and 1.3.34 --- the latest kernel that I was indirectly involved in. h](hlabel)}(hhh]h1}(hj8hhhNhNubah}(h]h ]h"]h$]h&]uh1j6hj2hhhNhNubh)}(hI cannot recollect what kernel version I looked at, then, presumably 1.2.13 and 1.3.34 --- the latest kernel that I was indirectly involved in.h]hI cannot recollect what kernel version I looked at, then, presumably 1.2.13 and 1.3.34 --- the latest kernel that I was indirectly involved in.}(hjEhhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhKLhj2ubeh}(h]jah ]h"]f1ah$]h&]jajKjjuh1j0hhhKKhjhhubh)}(hXI decided to start a discussion on how to make all the Linux CD-ROM drivers behave more uniformly. I began by contacting the developers of the many CD-ROM drivers found in the Linux kernel. Their reactions encouraged me to write the Uniform CD-ROM Driver which this document is intended to describe. The implementation of the Uniform CD-ROM Driver is in the file `cdrom.c`. This driver is intended to be an additional software layer that sits on top of the low-level device drivers for each CD-ROM drive. By adding this additional layer, it is possible to have all the different CD-ROM devices behave **exactly** the same (insofar as the underlying hardware will allow).h](hXkI decided to start a discussion on how to make all the Linux CD-ROM drivers behave more uniformly. I began by contacting the developers of the many CD-ROM drivers found in the Linux kernel. Their reactions encouraged me to write the Uniform CD-ROM Driver which this document is intended to describe. The implementation of the Uniform CD-ROM Driver is in the file }(hjZhhhNhNubj@)}(h `cdrom.c`h]hcdrom.c}(hjbhhhNhNubah}(h]h ]h"]h$]h&]uh1j?hjZubh. This driver is intended to be an additional software layer that sits on top of the low-level device drivers for each CD-ROM drive. By adding this additional layer, it is possible to have all the different CD-ROM devices behave }(hjZhhhNhNubhstrong)}(h **exactly**h]hexactly}(hjvhhhNhNubah}(h]h ]h"]h$]h&]uh1jthjZubh: the same (insofar as the underlying hardware will allow).}(hjZhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhKPhjhhubh)}(hXThe goal of the Uniform CD-ROM Driver is **not** to alienate driver developers whohave not yet taken steps to support this effort. The goal of Uniform CD-ROM Driver is simply to give people writing application programs for CD-ROM drives **one** Linux CD-ROM interface with consistent behavior for all CD-ROM devices. In addition, this also provides a consistent interface between the low-level device driver code and the Linux kernel. Care is taken that 100% compatibility exists with the data structures and programmer's interface defined in `cdrom.h`. This guide was written to help CD-ROM driver developers adapt their code to use the Uniform CD-ROM Driver code defined in `cdrom.c`.h](h)The goal of the Uniform CD-ROM Driver is }(hjhhhNhNubju)}(h**not**h]hnot}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jthjubh to alienate driver developers whohave not yet taken steps to support this effort. The goal of Uniform CD-ROM Driver is simply to give people writing application programs for CD-ROM drives }(hjhhhNhNubju)}(h**one**h]hone}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jthjubhX- Linux CD-ROM interface with consistent behavior for all CD-ROM devices. In addition, this also provides a consistent interface between the low-level device driver code and the Linux kernel. Care is taken that 100% compatibility exists with the data structures and programmer’s interface defined in }(hjhhhNhNubj@)}(h `cdrom.h`h]hcdrom.h}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1j?hjubh|. This guide was written to help CD-ROM driver developers adapt their code to use the Uniform CD-ROM Driver code defined in }(hjhhhNhNubj@)}(h `cdrom.c`h]hcdrom.c}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1j?hjubh.}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhK[hjhhubh)}(hXPersonally, I think that the most important hardware interfaces are the IDE/ATAPI drives and, of course, the SCSI drives, but as prices of hardware drop continuously, it is also likely that people may have more than one CD-ROM drive, possibly of mixed types. It is important that these drives behave in the same way. In December 1994, one of the cheapest CD-ROM drives was a Philips cm206, a double-speed proprietary drive. In the months that I was busy writing a Linux driver for it, proprietary drives became obsolete and IDE/ATAPI drives became the standard. At the time of the last update to this document (November 1997) it is becoming difficult to even **find** anything less than a 16 speed CD-ROM drive, and 24 speed drives are common.h](hXPersonally, I think that the most important hardware interfaces are the IDE/ATAPI drives and, of course, the SCSI drives, but as prices of hardware drop continuously, it is also likely that people may have more than one CD-ROM drive, possibly of mixed types. It is important that these drives behave in the same way. In December 1994, one of the cheapest CD-ROM drives was a Philips cm206, a double-speed proprietary drive. In the months that I was busy writing a Linux driver for it, proprietary drives became obsolete and IDE/ATAPI drives became the standard. At the time of the last update to this document (November 1997) it is becoming difficult to even }(hjhhhNhNubju)}(h**find**h]hfind}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jthjubhL anything less than a 16 speed CD-ROM drive, and 24 speed drives are common.}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhKfhjhhubhtarget)}(h.. _cdrom_api:h]h}(h]h ]h"]h$]h&]j cdrom-apiuh1jhKrhjhhhh referencedKubeh}(h] introductionah ]h"] introductionah$]h&]uh1hhhhhhhhK ubh)}(hhh](h)}(h,Standardizing through another software levelh]h,Standardizing through another software level}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjhhhhhKuubh)}(hXhAt the time this document was conceived, all drivers directly implemented the CD-ROM *ioctl()* calls through their own routines. This led to the danger of different drivers forgetting to do important things like checking that the user was giving the driver valid data. More importantly, this led to the divergence of behavior, which has already been discussed.h](hUAt the time this document was conceived, all drivers directly implemented the CD-ROM }(hj+hhhNhNubjT)}(h *ioctl()*h]hioctl()}(hj3hhhNhNubah}(h]h ]h"]h$]h&]uh1jShj+ubhX  calls through their own routines. This led to the danger of different drivers forgetting to do important things like checking that the user was giving the driver valid data. More importantly, this led to the divergence of behavior, which has already been discussed.}(hj+hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhKwhjhhubh)}(hXFor this reason, the Uniform CD-ROM Driver was created to enforce consistent CD-ROM drive behavior, and to provide a common set of services to the various low-level CD-ROM device drivers. The Uniform CD-ROM Driver now provides another software-level, that separates the *ioctl()* and *open()* implementation from the actual hardware implementation. Note that this effort has made few changes which will affect a user's application programs. The greatest change involved moving the contents of the various low-level CD-ROM drivers\' header files to the kernel's cdrom directory. This was done to help ensure that the user is only presented with only one cdrom interface, the interface defined in `cdrom.h`.h](hXFor this reason, the Uniform CD-ROM Driver was created to enforce consistent CD-ROM drive behavior, and to provide a common set of services to the various low-level CD-ROM device drivers. The Uniform CD-ROM Driver now provides another software-level, that separates the }(hjKhhhNhNubjT)}(h *ioctl()*h]hioctl()}(hjShhhNhNubah}(h]h ]h"]h$]h&]uh1jShjKubh and }(hjKhhhNhNubjT)}(h*open()*h]hopen()}(hjehhhNhNubah}(h]h ]h"]h$]h&]uh1jShjKubhX implementation from the actual hardware implementation. Note that this effort has made few changes which will affect a user’s application programs. The greatest change involved moving the contents of the various low-level CD-ROM drivers' header files to the kernel’s cdrom directory. This was done to help ensure that the user is only presented with only one cdrom interface, the interface defined in }(hjKhhhNhNubj@)}(h `cdrom.h`h]hcdrom.h}(hjwhhhNhNubah}(h]h ]h"]h$]h&]uh1j?hjKubh.}(hjKhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhK~hjhhubh)}(hX'CD-ROM drives are specific enough (i. e., different from other block-devices such as floppy or hard disc drives), to define a set of common **CD-ROM device operations**, *_dops*. These operations are different from the classical block-device file operations, *_fops*.h](hCD-ROM drives are specific enough (i. e., different from other block-devices such as floppy or hard disc drives), to define a set of common }(hjhhhNhNubju)}(h**CD-ROM device operations**h]hCD-ROM device operations}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jthjubh, }(hjhhhNhNubjT)}(h*_dops*h]h_dops}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubhR. These operations are different from the classical block-device file operations, }(hjhhhNhNubjT)}(h*_fops*h]h_fops}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubh.}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhKhjhhubh)}(hThe routines for the Uniform CD-ROM Driver interface level are implemented in the file `cdrom.c`. In this file, the Uniform CD-ROM Driver interfaces with the kernel as a block device by registering the following general *struct file_operations*::h](hWThe routines for the Uniform CD-ROM Driver interface level are implemented in the file }(hjhhhNhNubj@)}(h `cdrom.c`h]hcdrom.c}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1j?hjubh|. In this file, the Uniform CD-ROM Driver interfaces with the kernel as a block device by registering the following general }(hjhhhNhNubjT)}(h*struct file_operations*h]hstruct file_operations}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubh:}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhKhjhhubh literal_block)}(hXqstruct file_operations cdrom_fops = { NULL, /* lseek */ block _read , /* read--general block-dev read */ block _write, /* write--general block-dev write */ NULL, /* readdir */ NULL, /* select */ cdrom_ioctl, /* ioctl */ NULL, /* mmap */ cdrom_open, /* open */ cdrom_release, /* release */ NULL, /* fsync */ NULL, /* fasync */ NULL /* revalidate */ };h]hXqstruct file_operations cdrom_fops = { NULL, /* lseek */ block _read , /* read--general block-dev read */ block _write, /* write--general block-dev write */ NULL, /* readdir */ NULL, /* select */ cdrom_ioctl, /* ioctl */ NULL, /* mmap */ cdrom_open, /* open */ cdrom_release, /* release */ NULL, /* fsync */ NULL, /* fasync */ NULL /* revalidate */ };}hjsbah}(h]h ]h"]h$]h&] xml:spacepreserveuh1jhhhKhjhhubh)}(hXEvery active CD-ROM device shares this *struct*. The routines declared above are all implemented in `cdrom.c`, since this file is the place where the behavior of all CD-ROM-devices is defined and standardized. The actual interface to the various types of CD-ROM hardware is still performed by various low-level CD-ROM-device drivers. These routines simply implement certain **capabilities** that are common to all CD-ROM (and really, all removable-media devices).h](h'Every active CD-ROM device shares this }(hjhhhNhNubjT)}(h*struct*h]hstruct}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubh5. The routines declared above are all implemented in }(hjhhhNhNubj@)}(h `cdrom.c`h]hcdrom.c}(hj1hhhNhNubah}(h]h ]h"]h$]h&]uh1j?hjubhX , since this file is the place where the behavior of all CD-ROM-devices is defined and standardized. The actual interface to the various types of CD-ROM hardware is still performed by various low-level CD-ROM-device drivers. These routines simply implement certain }(hjhhhNhNubju)}(h**capabilities**h]h capabilities}(hjChhhNhNubah}(h]h ]h"]h$]h&]uh1jthjubhI that are common to all CD-ROM (and really, all removable-media devices).}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhKhjhhubh)}(hXyRegistration of a low-level CD-ROM device driver is now done through the general routines in `cdrom.c`, not through the Virtual File System (VFS) any more. The interface implemented in `cdrom.c` is carried out through two general structures that contain information about the capabilities of the driver, and the specific drives on which the driver operates. The structures are:h](h]Registration of a low-level CD-ROM device driver is now done through the general routines in }(hj[hhhNhNubj@)}(h `cdrom.c`h]hcdrom.c}(hjchhhNhNubah}(h]h ]h"]h$]h&]uh1j?hj[ubhS, not through the Virtual File System (VFS) any more. The interface implemented in }(hj[hhhNhNubj@)}(h `cdrom.c`h]hcdrom.c}(hjuhhhNhNubah}(h]h ]h"]h$]h&]uh1j?hj[ubh is carried out through two general structures that contain information about the capabilities of the driver, and the specific drives on which the driver operates. The structures are:}(hj[hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhKhjhhubhdefinition_list)}(hhh](hdefinition_list_item)}(hX cdrom_device_ops This structure contains information about the low-level driver for a CD-ROM device. This structure is conceptually connected to the major number of the device (although some drivers may have different major numbers, as is the case for the IDE driver). h](hterm)}(hcdrom_device_opsh]hcdrom_device_ops}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jhhhKhjubh definition)}(hhh]h)}(hThis structure contains information about the low-level driver for a CD-ROM device. This structure is conceptually connected to the major number of the device (although some drivers may have different major numbers, as is the case for the IDE driver).h]hThis structure contains information about the low-level driver for a CD-ROM device. This structure is conceptually connected to the major number of the device (although some drivers may have different major numbers, as is the case for the IDE driver).}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhKhjubah}(h]h ]h"]h$]h&]uh1jhjubeh}(h]h ]h"]h$]h&]uh1jhhhKhjubj)}(hcdrom_device_info This structure contains information about a particular CD-ROM drive, such as its device name, speed, etc. This structure is conceptually connected to the minor number of the device. h](j)}(hcdrom_device_infoh]hcdrom_device_info}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jhhhKhjubj)}(hhh]h)}(hThis structure contains information about a particular CD-ROM drive, such as its device name, speed, etc. This structure is conceptually connected to the minor number of the device.h]hThis structure contains information about a particular CD-ROM drive, such as its device name, speed, etc. This structure is conceptually connected to the minor number of the device.}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhKhjubah}(h]h ]h"]h$]h&]uh1jhjubeh}(h]h ]h"]h$]h&]uh1jhhhKhjhhubeh}(h]h ]h"]h$]h&]uh1jhjhhhhhNubh)}(h~Registering a particular CD-ROM drive with the Uniform CD-ROM Driver is done by the low-level device driver though a call to::h]h}Registering a particular CD-ROM drive with the Uniform CD-ROM Driver is done by the low-level device driver though a call to:}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhKhjhhubj)}(h8register_cdrom(struct cdrom_device_info * _info)h]h8register_cdrom(struct cdrom_device_info * _info)}hj sbah}(h]h ]h"]h$]h&]jjuh1jhhhKhjhhubh)}(hXThe device information structure, *_info*, contains all the information needed for the kernel to interface with the low-level CD-ROM device driver. One of the most important entries in this structure is a pointer to the *cdrom_device_ops* structure of the low-level driver.h](h"The device information structure, }(hjhhhNhNubjT)}(h*_info*h]h _info}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubh, contains all the information needed for the kernel to interface with the low-level CD-ROM device driver. One of the most important entries in this structure is a pointer to the }(hjhhhNhNubjT)}(h*cdrom_device_ops*h]hcdrom_device_ops}(hj2hhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubh# structure of the low-level driver.}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhKhjhhubh)}(hXBThe device operations structure, *cdrom_device_ops*, contains a list of pointers to the functions which are implemented in the low-level device driver. When `cdrom.c` accesses a CD-ROM device, it does it through the functions in this structure. It is impossible to know all the capabilities of future CD-ROM drives, so it is expected that this list may need to be expanded from time to time as new technologies are developed. For example, CD-R and CD-R/W drives are beginning to become popular, and support will soon need to be added for them. For now, the current *struct* is::h](h!The device operations structure, }(hjJhhhNhNubjT)}(h*cdrom_device_ops*h]hcdrom_device_ops}(hjRhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjJubhj, contains a list of pointers to the functions which are implemented in the low-level device driver. When }(hjJhhhNhNubj@)}(h `cdrom.c`h]hcdrom.c}(hjdhhhNhNubah}(h]h ]h"]h$]h&]uh1j?hjJubhX accesses a CD-ROM device, it does it through the functions in this structure. It is impossible to know all the capabilities of future CD-ROM drives, so it is expected that this list may need to be expanded from time to time as new technologies are developed. For example, CD-R and CD-R/W drives are beginning to become popular, and support will soon need to be added for them. For now, the current }(hjJhhhNhNubjT)}(h*struct*h]hstruct}(hjvhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjJubh is:}(hjJhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhKhjhhubj)}(hXKstruct cdrom_device_ops { int (*open)(struct cdrom_device_info *, int) void (*release)(struct cdrom_device_info *); int (*drive_status)(struct cdrom_device_info *, int); unsigned int (*check_events)(struct cdrom_device_info *, unsigned int, int); int (*media_changed)(struct cdrom_device_info *, int); int (*tray_move)(struct cdrom_device_info *, int); int (*lock_door)(struct cdrom_device_info *, int); int (*select_speed)(struct cdrom_device_info *, unsigned long); int (*get_last_session) (struct cdrom_device_info *, struct cdrom_multisession *); int (*get_mcn)(struct cdrom_device_info *, struct cdrom_mcn *); int (*reset)(struct cdrom_device_info *); int (*audio_ioctl)(struct cdrom_device_info *, unsigned int, void *); const int capability; /* capability flags */ int (*generic_packet)(struct cdrom_device_info *, struct packet_command *); };h]hXKstruct cdrom_device_ops { int (*open)(struct cdrom_device_info *, int) void (*release)(struct cdrom_device_info *); int (*drive_status)(struct cdrom_device_info *, int); unsigned int (*check_events)(struct cdrom_device_info *, unsigned int, int); int (*media_changed)(struct cdrom_device_info *, int); int (*tray_move)(struct cdrom_device_info *, int); int (*lock_door)(struct cdrom_device_info *, int); int (*select_speed)(struct cdrom_device_info *, unsigned long); int (*get_last_session) (struct cdrom_device_info *, struct cdrom_multisession *); int (*get_mcn)(struct cdrom_device_info *, struct cdrom_mcn *); int (*reset)(struct cdrom_device_info *); int (*audio_ioctl)(struct cdrom_device_info *, unsigned int, void *); const int capability; /* capability flags */ int (*generic_packet)(struct cdrom_device_info *, struct packet_command *); };}hjsbah}(h]h ]h"]h$]h&]jjuh1jhhhKhjhhubh)}(hXWhen a low-level device driver implements one of these capabilities, it should add a function pointer to this *struct*. When a particular function is not implemented, however, this *struct* should contain a NULL instead. The *capability* flags specify the capabilities of the CD-ROM hardware and/or low-level CD-ROM driver when a CD-ROM drive is registered with the Uniform CD-ROM Driver.h](hnWhen a low-level device driver implements one of these capabilities, it should add a function pointer to this }(hjhhhNhNubjT)}(h*struct*h]hstruct}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubh?. When a particular function is not implemented, however, this }(hjhhhNhNubjT)}(h*struct*h]hstruct}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubh$ should contain a NULL instead. The }(hjhhhNhNubjT)}(h *capability*h]h capability}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubh flags specify the capabilities of the CD-ROM hardware and/or low-level CD-ROM driver when a CD-ROM drive is registered with the Uniform CD-ROM Driver.}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhKhjhhubh)}(hXNote that most functions have fewer parameters than their *blkdev_fops* counterparts. This is because very little of the information in the structures *inode* and *file* is used. For most drivers, the main parameter is the *struct* *cdrom_device_info*, from which the major and minor number can be extracted. (Most low-level CD-ROM drivers don't even look at the major and minor number though, since many of them only support one device.) This will be available through *dev* in *cdrom_device_info* described below.h](h:Note that most functions have fewer parameters than their }(hjhhhNhNubjT)}(h *blkdev_fops*h]h blkdev_fops}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubhP counterparts. This is because very little of the information in the structures }(hjhhhNhNubjT)}(h*inode*h]hinode}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubh and }(hjhhhNhNubjT)}(h*file*h]hfile}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubh6 is used. For most drivers, the main parameter is the }(hjhhhNhNubjT)}(h*struct*h]hstruct}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubh }(hjhhhNhNubjT)}(h*cdrom_device_info*h]hcdrom_device_info}(hj0hhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubh, from which the major and minor number can be extracted. (Most low-level CD-ROM drivers don’t even look at the major and minor number though, since many of them only support one device.) This will be available through }(hjhhhNhNubjT)}(h*dev*h]hdev}(hjBhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubh in }(hjhhhNhNubjT)}(h*cdrom_device_info*h]hcdrom_device_info}(hjThhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubh described below.}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhKhjhhubh)}(hwThe drive-specific, minor-like information that is registered with `cdrom.c`, currently contains the following fields::h](hCThe drive-specific, minor-like information that is registered with }(hjlhhhNhNubj@)}(h `cdrom.c`h]hcdrom.c}(hjthhhNhNubah}(h]h ]h"]h$]h&]uh1j?hjlubh*, currently contains the following fields:}(hjlhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhKhjhhubj)}(hXstruct cdrom_device_info { const struct cdrom_device_ops * ops; /* device operations for this major */ struct list_head list; /* linked list of all device_info */ struct gendisk * disk; /* matching block layer disk */ void * handle; /* driver-dependent data */ int mask; /* mask of capability: disables them */ int speed; /* maximum speed for reading data */ int capacity; /* number of discs in a jukebox */ unsigned int options:30; /* options flags */ unsigned mc_flags:2; /* media-change buffer flags */ unsigned int vfs_events; /* cached events for vfs path */ unsigned int ioctl_events; /* cached events for ioctl path */ int use_count; /* number of times device is opened */ char name[20]; /* name of the device type */ __u8 sanyo_slot : 2; /* Sanyo 3-CD changer support */ __u8 keeplocked : 1; /* CDROM_LOCKDOOR status */ __u8 reserved : 5; /* not used yet */ int cdda_method; /* see CDDA_* flags */ __u8 last_sense; /* saves last sense key */ __u8 media_written; /* dirty flag, DVD+RW bookkeeping */ unsigned short mmc3_profile; /* current MMC3 profile */ int for_data; /* unknown:TBD */ int (*exit)(struct cdrom_device_info *);/* unknown:TBD */ int mrw_mode_page; /* which MRW mode page is in use */ };h]hXstruct cdrom_device_info { const struct cdrom_device_ops * ops; /* device operations for this major */ struct list_head list; /* linked list of all device_info */ struct gendisk * disk; /* matching block layer disk */ void * handle; /* driver-dependent data */ int mask; /* mask of capability: disables them */ int speed; /* maximum speed for reading data */ int capacity; /* number of discs in a jukebox */ unsigned int options:30; /* options flags */ unsigned mc_flags:2; /* media-change buffer flags */ unsigned int vfs_events; /* cached events for vfs path */ unsigned int ioctl_events; /* cached events for ioctl path */ int use_count; /* number of times device is opened */ char name[20]; /* name of the device type */ __u8 sanyo_slot : 2; /* Sanyo 3-CD changer support */ __u8 keeplocked : 1; /* CDROM_LOCKDOOR status */ __u8 reserved : 5; /* not used yet */ int cdda_method; /* see CDDA_* flags */ __u8 last_sense; /* saves last sense key */ __u8 media_written; /* dirty flag, DVD+RW bookkeeping */ unsigned short mmc3_profile; /* current MMC3 profile */ int for_data; /* unknown:TBD */ int (*exit)(struct cdrom_device_info *);/* unknown:TBD */ int mrw_mode_page; /* which MRW mode page is in use */ };}hjsbah}(h]h ]h"]h$]h&]jjuh1jhhhKhjhhubh)}(hUsing this *struct*, a linked list of the registered minor devices is built, using the *next* field. The device number, the device operations struct and specifications of properties of the drive are stored in this structure.h](h Using this }(hjhhhNhNubjT)}(h*struct*h]hstruct}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubhD, a linked list of the registered minor devices is built, using the }(hjhhhNhNubjT)}(h*next*h]hnext}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubh field. The device number, the device operations struct and specifications of properties of the drive are stored in this structure.}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhjhhubh)}(hXThe *mask* flags can be used to mask out some of the capabilities listed in *ops->capability*, if a specific drive doesn't support a feature of the driver. The value *speed* specifies the maximum head-rate of the drive, measured in units of normal audio speed (176kB/sec raw data or 150kB/sec file system data). The parameters are declared *const* because they describe properties of the drive, which don't change after registration.h](hThe }(hjhhhNhNubjT)}(h*mask*h]hmask}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubhB flags can be used to mask out some of the capabilities listed in }(hjhhhNhNubjT)}(h*ops->capability*h]hops->capability}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubhK, if a specific drive doesn’t support a feature of the driver. The value }(hjhhhNhNubjT)}(h*speed*h]hspeed}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubh specifies the maximum head-rate of the drive, measured in units of normal audio speed (176kB/sec raw data or 150kB/sec file system data). The parameters are declared }(hjhhhNhNubjT)}(h*const*h]hconst}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubhX because they describe properties of the drive, which don’t change after registration.}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhjhhubh)}(hXA few registers contain variables local to the CD-ROM drive. The flags *options* are used to specify how the general CD-ROM routines should behave. These various flags registers should provide enough flexibility to adapt to the different users' wishes (and **not** the `arbitrary` wishes of the author of the low-level device driver, as is the case in the old scheme). The register *mc_flags* is used to buffer the information from *media_changed()* to two separate queues. Other data that is specific to a minor drive, can be accessed through *handle*, which can point to a data structure specific to the low-level driver. The fields *use_count*, *next*, *options* and *mc_flags* need not be initialized.h](hGA few registers contain variables local to the CD-ROM drive. The flags }(hj"hhhNhNubjT)}(h *options*h]hoptions}(hj*hhhNhNubah}(h]h ]h"]h$]h&]uh1jShj"ubh are used to specify how the general CD-ROM routines should behave. These various flags registers should provide enough flexibility to adapt to the different users’ wishes (and }(hj"hhhNhNubju)}(h**not**h]hnot}(hj<hhhNhNubah}(h]h ]h"]h$]h&]uh1jthj"ubh the }(hj"hhhNhNubj@)}(h `arbitrary`h]h arbitrary}(hjNhhhNhNubah}(h]h ]h"]h$]h&]uh1j?hj"ubhf wishes of the author of the low-level device driver, as is the case in the old scheme). The register }(hj"hhhNhNubjT)}(h *mc_flags*h]hmc_flags}(hj`hhhNhNubah}(h]h ]h"]h$]h&]uh1jShj"ubh( is used to buffer the information from }(hj"hhhNhNubjT)}(h*media_changed()*h]hmedia_changed()}(hjrhhhNhNubah}(h]h ]h"]h$]h&]uh1jShj"ubh_ to two separate queues. Other data that is specific to a minor drive, can be accessed through }(hj"hhhNhNubjT)}(h*handle*h]hhandle}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShj"ubhS, which can point to a data structure specific to the low-level driver. The fields }(hj"hhhNhNubjT)}(h *use_count*h]h use_count}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShj"ubh, }(hj"hhhNhNubjT)}(h*next*h]hnext}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShj"ubh, }hj"sbjT)}(h *options*h]hoptions}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShj"ubh and }(hj"hhhNhNubjT)}(h *mc_flags*h]hmc_flags}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShj"ubh need not be initialized.}(hj"hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhM%hjhhubh)}(hXThe intermediate software layer that `cdrom.c` forms will perform some additional bookkeeping. The use count of the device (the number of processes that have the device opened) is registered in *use_count*. The function *cdrom_ioctl()* will verify the appropriate user-memory regions for read and write, and in case a location on the CD is transferred, it will `sanitize` the format by making requests to the low-level drivers in a standard format, and translating all formats between the user-software and low level drivers. This relieves much of the drivers' memory checking and format checking and translation. Also, the necessary structures will be declared on the program stack.h](h%The intermediate software layer that }(hjhhhNhNubj@)}(h `cdrom.c`h]hcdrom.c}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1j?hjubh forms will perform some additional bookkeeping. The use count of the device (the number of processes that have the device opened) is registered in }(hjhhhNhNubjT)}(h *use_count*h]h use_count}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubh. The function }(hjhhhNhNubjT)}(h*cdrom_ioctl()*h]h cdrom_ioctl()}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubh~ will verify the appropriate user-memory regions for read and write, and in case a location on the CD is transferred, it will }(hjhhhNhNubj@)}(h `sanitize`h]hsanitize}(hj" hhhNhNubah}(h]h ]h"]h$]h&]uh1j?hjubhX: the format by making requests to the low-level drivers in a standard format, and translating all formats between the user-software and low level drivers. This relieves much of the drivers’ memory checking and format checking and translation. Also, the necessary structures will be declared on the program stack.}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhM1hjhhubh)}(hXThe implementation of the functions should be as defined in the following sections. Two functions **must** be implemented, namely *open()* and *release()*. Other functions may be omitted, their corresponding capability flags will be cleared upon registration. Generally, a function returns zero on success and negative on error. A function call should return only after the command has completed, but of course waiting for the device should not use processor time.h](hbThe implementation of the functions should be as defined in the following sections. Two functions }(hj: hhhNhNubju)}(h**must**h]hmust}(hjB hhhNhNubah}(h]h ]h"]h$]h&]uh1jthj: ubh be implemented, namely }(hj: hhhNhNubjT)}(h*open()*h]hopen()}(hjT hhhNhNubah}(h]h ]h"]h$]h&]uh1jShj: ubh and }(hj: hhhNhNubjT)}(h *release()*h]h release()}(hjf hhhNhNubah}(h]h ]h"]h$]h&]uh1jShj: ubhX6. Other functions may be omitted, their corresponding capability flags will be cleared upon registration. Generally, a function returns zero on success and negative on error. A function call should return only after the command has completed, but of course waiting for the device should not use processor time.}(hj: hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhM<hjhhubj)}(h4int open(struct cdrom_device_info *cdi, int purpose)h]h4int open(struct cdrom_device_info *cdi, int purpose)}hj~ sbah}(h]h ]h"]h$]h&]jjuh1jhhhMFhjhhubh)}(hU*Open()* should try to open the device for a specific *purpose*, which can be either:h](jT)}(h*Open()*h]hOpen()}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1jShj ubh. should try to open the device for a specific }(hj hhhNhNubjT)}(h *purpose*h]hpurpose}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1jShj ubh, which can be either:}(hj hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMHhjhhubj)}(hhh](j)}(hTOpen for reading data, as done by `mount()` (2), or the user commands `dd` or `cat`.h]h)}(hTOpen for reading data, as done by `mount()` (2), or the user commands `dd` or `cat`.h](h"Open for reading data, as done by }(hj hhhNhNubj@)}(h `mount()`h]hmount()}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1j?hj ubh (2), or the user commands }(hj hhhNhNubj@)}(h`dd`h]hdd}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1j?hj ubh or }(hj hhhNhNubj@)}(h`cat`h]hcat}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1j?hj ubh.}(hj hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMKhj ubah}(h]h ]h"]h$]h&]uh1jhj hhhhhNubj)}(hAOpen for *ioctl* commands, as done by audio-CD playing programs. h]h)}(h@Open for *ioctl* commands, as done by audio-CD playing programs.h](h Open for }(hj hhhNhNubjT)}(h*ioctl*h]hioctl}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1jShj ubh0 commands, as done by audio-CD playing programs.}(hj hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMMhj ubah}(h]h ]h"]h$]h&]uh1jhj hhhhhNubeh}(h]h ]h"]h$]h&]j5j6uh1jhhhMKhjhhubh)}(hNotice that any strategic code (closing tray upon *open()*, etc.) is done by the calling routine in `cdrom.c`, so the low-level routine should only be concerned with proper initialization, such as spinning up the disc, etc.h](h2Notice that any strategic code (closing tray upon }(hj; hhhNhNubjT)}(h*open()*h]hopen()}(hjC hhhNhNubah}(h]h ]h"]h$]h&]uh1jShj; ubh*, etc.) is done by the calling routine in }(hj; hhhNhNubj@)}(h `cdrom.c`h]hcdrom.c}(hjU hhhNhNubah}(h]h ]h"]h$]h&]uh1j?hj; ubhr, so the low-level routine should only be concerned with proper initialization, such as spinning up the disc, etc.}(hj; hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMOhjhhubj)}(h+void release(struct cdrom_device_info *cdi)h]h+void release(struct cdrom_device_info *cdi)}hjm sbah}(h]h ]h"]h$]h&]jjuh1jhhhMVhjhhubh)}(hXDevice-specific actions should be taken such as spinning down the device. However, strategic actions such as ejection of the tray, or unlocking the door, should be left over to the general routine *cdrom_release()*. This is the only function returning type *void*.h](hDevice-specific actions should be taken such as spinning down the device. However, strategic actions such as ejection of the tray, or unlocking the door, should be left over to the general routine }(hj{ hhhNhNubjT)}(h*cdrom_release()*h]hcdrom_release()}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1jShj{ ubh+. This is the only function returning type }(hj{ hhhNhNubjT)}(h*void*h]hvoid}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1jShj{ ubh.}(hj{ hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMXhjhhubj)}(h.. _cdrom_drive_status:h]h}(h]h ]h"]h$]h&]jcdrom-drive-statusuh1jhM]hjhhhhjKubj)}(hdev*, the start of the last session of the current disc should be returned in the pointer argument *ms_info*. Note that routines in `cdrom.c` have sanitized this argument: its requested format will **always** be of the type *CDROM_LBA* (linear block addressing mode), whatever the calling software requested. But sanitization goes even further: the low-level implementation may return the requested information in *CDROM_MSF* format if it wishes so (setting the *ms_info->addr_format* field appropriately, of course) and the routines in `cdrom.c` will make the transformation if necessary. The return value is 0 upon success.h](h5This function should implement the old corresponding }(hj hhhNhNubjT)}(h *ioctl()*h]hioctl()}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1jShj ubh . For device }(hj hhhNhNubjT)}(h *cdi->dev*h]hcdi->dev}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1jShj ubh_, the start of the last session of the current disc should be returned in the pointer argument }(hj hhhNhNubjT)}(h *ms_info*h]hms_info}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1jShj ubh. Note that routines in }(hj hhhNhNubj@)}(h `cdrom.c`h]hcdrom.c}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1j?hj ubh9 have sanitized this argument: its requested format will }(hj hhhNhNubju)}(h **always**h]halways}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1jthj ubh be of the type }(hj hhhNhNubjT)}(h *CDROM_LBA*h]h CDROM_LBA}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1jShj ubh (linear block addressing mode), whatever the calling software requested. But sanitization goes even further: the low-level implementation may return the requested information in }(hj hhhNhNubjT)}(h *CDROM_MSF*h]h CDROM_MSF}(hj/ hhhNhNubah}(h]h ]h"]h$]h&]uh1jShj ubh% format if it wishes so (setting the }(hj hhhNhNubjT)}(h*ms_info->addr_format*h]hms_info->addr_format}(hjA hhhNhNubah}(h]h ]h"]h$]h&]uh1jShj ubh5 field appropriately, of course) and the routines in }(hj hhhNhNubj@)}(h `cdrom.c`h]hcdrom.c}(hjS hhhNhNubah}(h]h ]h"]h$]h&]uh1j?hj ubhO will make the transformation if necessary. The return value is 0 upon success.}(hj hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhjhhubj)}(hMint get_mcn(struct cdrom_device_info *cdi, struct cdrom_mcn *mcn)h]hMint get_mcn(struct cdrom_device_info *cdi, struct cdrom_mcn *mcn)}hjk sbah}(h]h ]h"]h$]h&]jjuh1jhhhMhjhhubh)}(hXSome discs carry a `Media Catalog Number` (MCN), also called `Universal Product Code` (UPC). This number should reflect the number that is generally found in the bar-code on the product. Unfortunately, the few discs that carry such a number on the disc don't even use the same format. The return argument to this function is a pointer to a pre-declared memory region of type *struct cdrom_mcn*. The MCN is expected as a 13-character string, terminated by a null-character.h](hSome discs carry a }(hjy hhhNhNubj@)}(h`Media Catalog Number`h]hMedia Catalog Number}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1j?hjy ubh (MCN), also called }(hjy hhhNhNubj@)}(h`Universal Product Code`h]hUniversal Product Code}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1j?hjy ubhX$ (UPC). This number should reflect the number that is generally found in the bar-code on the product. Unfortunately, the few discs that carry such a number on the disc don’t even use the same format. The return argument to this function is a pointer to a pre-declared memory region of type }(hjy hhhNhNubjT)}(h*struct cdrom_mcn*h]hstruct cdrom_mcn}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1jShjy ubhO. The MCN is expected as a 13-character string, terminated by a null-character.}(hjy hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhjhhubj)}(h(int reset(struct cdrom_device_info *cdi)h]h(int reset(struct cdrom_device_info *cdi)}hj sbah}(h]h ]h"]h$]h&]jjuh1jhhhMhjhhubh)}(hXjThis call should perform a hard-reset on the drive (although in circumstances that a hard-reset is necessary, a drive may very well not listen to commands anymore). Preferably, control is returned to the caller only after the drive has finished resetting. If the drive is no longer listening, it may be wise for the underlying low-level cdrom driver to time out.h]hXjThis call should perform a hard-reset on the drive (although in circumstances that a hard-reset is necessary, a drive may very well not listen to commands anymore). Preferably, control is returned to the caller only after the drive has finished resetting. If the drive is no longer listening, it may be wise for the underlying low-level cdrom driver to time out.}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhMhjhhubj)}(h[int audio_ioctl(struct cdrom_device_info *cdi, unsigned int cmd, void *arg)h]h[int audio_ioctl(struct cdrom_device_info *cdi, unsigned int cmd, void *arg)}hj sbah}(h]h ]h"]h$]h&]jjuh1jhhhMhjhhubh)}(hXfSome of the CD-ROM-\ *ioctl()*\ 's defined in `cdrom.h` can be implemented by the routines described above, and hence the function *cdrom_ioctl* will use those. However, most *ioctl()*\ 's deal with audio-control. We have decided to leave these to be accessed through a single function, repeating the arguments *cmd* and *arg*. Note that the latter is of type *void*, rather than *unsigned long int*. The routine *cdrom_ioctl()* does do some useful things, though. It sanitizes the address format type to *CDROM_MSF* (Minutes, Seconds, Frames) for all audio calls. It also verifies the memory location of *arg*, and reserves stack-memory for the argument. This makes implementation of the *audio_ioctl()* much simpler than in the old driver scheme. For example, you may look up the function *cm206_audio_ioctl()* `cm206.c` that should be updated with this documentation.h](hSome of the CD-ROM- }(hj hhhNhNubjT)}(h *ioctl()*h]hioctl()}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1jShj ubh ‘s defined in }(hj hhhNhNubj@)}(h `cdrom.h`h]hcdrom.h}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1j?hj ubhL can be implemented by the routines described above, and hence the function }(hj hhhNhNubjT)}(h *cdrom_ioctl*h]h cdrom_ioctl}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShj ubh will use those. However, most }(hj hhhNhNubjT)}(h *ioctl()*h]hioctl()}(hj%hhhNhNubah}(h]h ]h"]h$]h&]uh1jShj ubh ‘s deal with audio-control. We have decided to leave these to be accessed through a single function, repeating the arguments }(hj hhhNhNubjT)}(h*cmd*h]hcmd}(hj7hhhNhNubah}(h]h ]h"]h$]h&]uh1jShj ubh and }(hj hhhNhNubjT)}(h*arg*h]harg}(hjIhhhNhNubah}(h]h ]h"]h$]h&]uh1jShj ubh". Note that the latter is of type }(hj hhhNhNubjT)}(h*void*h]hvoid}(hj[hhhNhNubah}(h]h ]h"]h$]h&]uh1jShj ubh, rather than }(hj hhhNhNubjT)}(h*unsigned long int*h]hunsigned long int}(hjmhhhNhNubah}(h]h ]h"]h$]h&]uh1jShj ubh. The routine }(hj hhhNhNubjT)}(h*cdrom_ioctl()*h]h cdrom_ioctl()}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShj ubhM does do some useful things, though. It sanitizes the address format type to }(hj hhhNhNubjT)}(h *CDROM_MSF*h]h CDROM_MSF}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShj ubhY (Minutes, Seconds, Frames) for all audio calls. It also verifies the memory location of }(hj hhhNhNubjT)}(h*arg*h]harg}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShj ubhO, and reserves stack-memory for the argument. This makes implementation of the }(hj hhhNhNubjT)}(h*audio_ioctl()*h]h audio_ioctl()}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShj ubhW much simpler than in the old driver scheme. For example, you may look up the function }(hj hhhNhNubjT)}(h*cm206_audio_ioctl()*h]hcm206_audio_ioctl()}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShj ubh }(hj hhhNhNubj@)}(h `cm206.c`h]hcm206.c}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1j?hj ubh0 that should be updated with this documentation.}(hj hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhjhhubh)}(hXAn unimplemented ioctl should return *-ENOSYS*, but a harmless request (e. g., *CDROMSTART*) may be ignored by returning 0 (success). Other errors should be according to the standards, whatever they are. When an error is returned by the low-level driver, the Uniform CD-ROM Driver tries whenever possible to return the error code to the calling program. (We may decide to sanitize the return value in *cdrom_ioctl()* though, in order to guarantee a uniform interface to the audio-player software.)h](h%An unimplemented ioctl should return }(hjhhhNhNubjT)}(h *-ENOSYS*h]h-ENOSYS}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubh!, but a harmless request (e. g., }(hjhhhNhNubjT)}(h *CDROMSTART*h]h CDROMSTART}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubhX6) may be ignored by returning 0 (success). Other errors should be according to the standards, whatever they are. When an error is returned by the low-level driver, the Uniform CD-ROM Driver tries whenever possible to return the error code to the calling program. (We may decide to sanitize the return value in }(hjhhhNhNubjT)}(h*cdrom_ioctl()*h]h cdrom_ioctl()}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubhQ though, in order to guarantee a uniform interface to the audio-player software.)}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhjhhubj)}(h_int dev_ioctl(struct cdrom_device_info *cdi, unsigned int cmd, unsigned long arg)h]h_int dev_ioctl(struct cdrom_device_info *cdi, unsigned int cmd, unsigned long arg)}hj5sbah}(h]h ]h"]h$]h&]jjuh1jhhhMhjhhubh)}(hXSome *ioctl()'s* seem to be specific to certain CD-ROM drives. That is, they are introduced to service some capabilities of certain drives. In fact, there are 6 different *ioctl()'s* for reading data, either in some particular kind of format, or audio data. Not many drives support reading audio tracks as data, I believe this is because of protection of copyrights of artists. Moreover, I think that if audio-tracks are supported, it should be done through the VFS and not via *ioctl()'s*. A problem here could be the fact that audio-frames are 2352 bytes long, so either the audio-file-system should ask for 75264 bytes at once (the least common multiple of 512 and 2352), or the drivers should bend their backs to cope with this incoherence (to which I would be opposed). Furthermore, it is very difficult for the hardware to find the exact frame boundaries, since there are no synchronization headers in audio frames. Once these issues are resolved, this code should be standardized in `cdrom.c`.h](hSome }(hjChhhNhNubjT)}(h *ioctl()'s*h]h ioctl()’s}(hjKhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjCubh seem to be specific to certain CD-ROM drives. That is, they are introduced to service some capabilities of certain drives. In fact, there are 6 different }(hjChhhNhNubjT)}(h *ioctl()'s*h]h ioctl()’s}(hj]hhhNhNubah}(h]h ]h"]h$]h&]uh1jShjCubhX( for reading data, either in some particular kind of format, or audio data. Not many drives support reading audio tracks as data, I believe this is because of protection of copyrights of artists. Moreover, I think that if audio-tracks are supported, it should be done through the VFS and not via }(hjChhhNhNubjT)}(h *ioctl()'s*h]h ioctl()’s}(hjohhhNhNubah}(h]h ]h"]h$]h&]uh1jShjCubhX. A problem here could be the fact that audio-frames are 2352 bytes long, so either the audio-file-system should ask for 75264 bytes at once (the least common multiple of 512 and 2352), or the drivers should bend their backs to cope with this incoherence (to which I would be opposed). Furthermore, it is very difficult for the hardware to find the exact frame boundaries, since there are no synchronization headers in audio frames. Once these issues are resolved, this code should be standardized in }(hjChhhNhNubj@)}(h `cdrom.c`h]hcdrom.c}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1j?hjCubh.}(hjChhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhjhhubh)}(hXfBecause there are so many *ioctl()'s* that seem to be introduced to satisfy certain drivers [#f2]_, any non-standard *ioctl()*\ s are routed through the call *dev_ioctl()*. In principle, `private` *ioctl()*\ 's should be numbered after the device's major number, and not the general CD-ROM *ioctl* number, `0x53`. Currently the non-supported *ioctl()'s* are:h](hBecause there are so many }(hjhhhNhNubjT)}(h *ioctl()'s*h]h ioctl()’s}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubh7 that seem to be introduced to satisfy certain drivers }(hjhhhNhNubj)}(h[#f2]_h]h2}(hjhhhNhNubah}(h]id2ah ]h"]h$]h&]jKjf2jjuh1jhjjKubh, any non-standard }(hjhhhNhNubjT)}(h *ioctl()*h]hioctl()}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubh s are routed through the call }(hjhhhNhNubjT)}(h *dev_ioctl()*h]h dev_ioctl()}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubh. In principle, }(hjhhhNhNubj@)}(h `private`h]hprivate}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1j?hjubh }(hjhhhNhNubjT)}(h *ioctl()*h]hioctl()}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubhX ‘s should be numbered after the device’s major number, and not the general CD-ROM }(hjhhhNhNubjT)}(h*ioctl*h]hioctl}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubh number, }(hjhhhNhNubj@)}(h`0x53`h]h0x53}(hj!hhhNhNubah}(h]h ]h"]h$]h&]uh1j?hjubh. Currently the non-supported }(hjhhhNhNubjT)}(h *ioctl()'s*h]h ioctl()’s}(hj3hhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubh are:}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhjhhubh block_quote)}(hzCDROMREADMODE1, CDROMREADMODE2, CDROMREADAUDIO, CDROMREADRAW, CDROMREADCOOKED, CDROMSEEK, CDROMPLAY-BLK and CDROM-READALL h]h)}(hyCDROMREADMODE1, CDROMREADMODE2, CDROMREADAUDIO, CDROMREADRAW, CDROMREADCOOKED, CDROMSEEK, CDROMPLAY-BLK and CDROM-READALLh]hyCDROMREADMODE1, CDROMREADMODE2, CDROMREADAUDIO, CDROMREADRAW, CDROMREADCOOKED, CDROMSEEK, CDROMPLAY-BLK and CDROM-READALL}(hjQhhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhMhjMubah}(h]h ]h"]h$]h&]uh1jKhhhMhjhhubj1)}(hFIs there software around that actually uses these? I'd be interested! h](j7)}(hhh]h2}(hjihhhNhNubah}(h]h ]h"]h$]h&]uh1j6hjehhhNhNubh)}(hEIs there software around that actually uses these? I'd be interested!h]hGIs there software around that actually uses these? I’d be interested!}(hjvhhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhM hjeubeh}(h]jah ]h"]f2ah$]h&]jajKjjuh1j0hhhM hjhhubj)}(h.. _cdrom_capabilities:h]h}(h]h ]h"]h$]h&]jcdrom-capabilitiesuh1jhM hjhhhhjKubh)}(hhh](h)}(hCD-ROM capabilitiesh]hCD-ROM capabilities}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjhhhhhMubh)}(hX7Instead of just implementing some *ioctl* calls, the interface in `cdrom.c` supplies the possibility to indicate the **capabilities** of a CD-ROM drive. This can be done by ORing any number of capability-constants that are defined in `cdrom.h` at the registration phase. Currently, the capabilities are any of::h](h"Instead of just implementing some }(hjhhhNhNubjT)}(h*ioctl*h]hioctl}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubh calls, the interface in }(hjhhhNhNubj@)}(h `cdrom.c`h]hcdrom.c}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1j?hjubh* supplies the possibility to indicate the }(hjhhhNhNubju)}(h**capabilities**h]h capabilities}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jthjubhe of a CD-ROM drive. This can be done by ORing any number of capability-constants that are defined in }(hjhhhNhNubj@)}(h `cdrom.h`h]hcdrom.h}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1j?hjubhC at the registration phase. Currently, the capabilities are any of:}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhjhhubj)}(hXCDC_CLOSE_TRAY /* can close tray by software control */ CDC_OPEN_TRAY /* can open tray */ CDC_LOCK /* can lock and unlock the door */ CDC_SELECT_SPEED /* can select speed, in units of * sim*150 ,kB/s */ CDC_SELECT_DISC /* drive is juke-box */ CDC_MULTI_SESSION /* can read sessions *> rm1* */ CDC_MCN /* can read Media Catalog Number */ CDC_MEDIA_CHANGED /* can report if disc has changed */ CDC_PLAY_AUDIO /* can perform audio-functions (play, pause, etc) */ CDC_RESET /* hard reset device */ CDC_IOCTLS /* driver has non-standard ioctls */ CDC_DRIVE_STATUS /* driver implements drive status */h]hXCDC_CLOSE_TRAY /* can close tray by software control */ CDC_OPEN_TRAY /* can open tray */ CDC_LOCK /* can lock and unlock the door */ CDC_SELECT_SPEED /* can select speed, in units of * sim*150 ,kB/s */ CDC_SELECT_DISC /* drive is juke-box */ CDC_MULTI_SESSION /* can read sessions *> rm1* */ CDC_MCN /* can read Media Catalog Number */ CDC_MEDIA_CHANGED /* can report if disc has changed */ CDC_PLAY_AUDIO /* can perform audio-functions (play, pause, etc) */ CDC_RESET /* hard reset device */ CDC_IOCTLS /* driver has non-standard ioctls */ CDC_DRIVE_STATUS /* driver implements drive status */}hjsbah}(h]h ]h"]h$]h&]jjuh1jhhhMhjhhubh)}(hXThe capability flag is declared *const*, to prevent drivers from accidentally tampering with the contents. The capability flags actually inform `cdrom.c` of what the driver can do. If the drive found by the driver does not have the capability, is can be masked out by the *cdrom_device_info* variable *mask*. For instance, the SCSI CD-ROM driver has implemented the code for loading and ejecting CD-ROM's, and hence its corresponding flags in *capability* will be set. But a SCSI CD-ROM drive might be a caddy system, which can't load the tray, and hence for this drive the *cdrom_device_info* struct will have set the *CDC_CLOSE_TRAY* bit in *mask*.h](h The capability flag is declared }(hj hhhNhNubjT)}(h*const*h]hconst}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShj ubhi, to prevent drivers from accidentally tampering with the contents. The capability flags actually inform }(hj hhhNhNubj@)}(h `cdrom.c`h]hcdrom.c}(hj%hhhNhNubah}(h]h ]h"]h$]h&]uh1j?hj ubhw of what the driver can do. If the drive found by the driver does not have the capability, is can be masked out by the }(hj hhhNhNubjT)}(h*cdrom_device_info*h]hcdrom_device_info}(hj7hhhNhNubah}(h]h ]h"]h$]h&]uh1jShj ubh variable }(hj hhhNhNubjT)}(h*mask*h]hmask}(hjIhhhNhNubah}(h]h ]h"]h$]h&]uh1jShj ubh. For instance, the SCSI CD-ROM driver has implemented the code for loading and ejecting CD-ROM’s, and hence its corresponding flags in }(hj hhhNhNubjT)}(h *capability*h]h capability}(hj[hhhNhNubah}(h]h ]h"]h$]h&]uh1jShj ubhy will be set. But a SCSI CD-ROM drive might be a caddy system, which can’t load the tray, and hence for this drive the }(hj hhhNhNubjT)}(h*cdrom_device_info*h]hcdrom_device_info}(hjmhhhNhNubah}(h]h ]h"]h$]h&]uh1jShj ubh struct will have set the }(hj hhhNhNubjT)}(h*CDC_CLOSE_TRAY*h]hCDC_CLOSE_TRAY}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShj ubh bit in }(hj hhhNhNubjT)}(h*mask*h]hmask}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShj ubh.}(hj hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhM%hjhhubh)}(hIIn the file `cdrom.c` you will encounter many constructions of the type::h](h In the file }(hjhhhNhNubj@)}(h `cdrom.c`h]hcdrom.c}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1j?hjubh3 you will encounter many constructions of the type:}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhM0hjhhubj)}(h9if (cdo->capability & ~cdi->mask & CDC _) ...h]h9if (cdo->capability & ~cdi->mask & CDC _) ...}hjsbah}(h]h ]h"]h$]h&]jjuh1jhhhM2hjhhubh)}(hThere is no *ioctl* to set the mask... The reason is that I think it is better to control the **behavior** rather than the **capabilities**.h](h There is no }(hjhhhNhNubjT)}(h*ioctl*h]hioctl}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubhK to set the mask... The reason is that I think it is better to control the }(hjhhhNhNubju)}(h **behavior**h]hbehavior}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jthjubh rather than the }(hjhhhNhNubju)}(h**capabilities**h]h capabilities}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jthjubh.}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhM4hjhhubeh}(h](cd-rom-capabilitiesjeh ]h"](cd-rom capabilitiescdrom_capabilitieseh$]h&]uh1hhjhhhhhMj }j!jsj }jjsjKubh)}(hhh](h)}(hOptionsh]hOptions}(hj)hhhNhNubah}(h]h ]h"]h$]h&]uh1hhj&hhhhhM9ubh)}(hX#A final flag register controls the **behavior** of the CD-ROM drives, in order to satisfy different users' wishes, hopefully independently of the ideas of the respective author who happened to have made the drive's support available to the Linux community. The current behavior options are::h](h#A final flag register controls the }(hj7hhhNhNubju)}(h **behavior**h]hbehavior}(hj?hhhNhNubah}(h]h ]h"]h$]h&]uh1jthj7ubh of the CD-ROM drives, in order to satisfy different users’ wishes, hopefully independently of the ideas of the respective author who happened to have made the drive’s support available to the Linux community. The current behavior options are:}(hj7hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhM;hj&hhubj)}(hXDCDO_AUTO_CLOSE /* try to close tray upon device open() */ CDO_AUTO_EJECT /* try to open tray on last device close() */ CDO_USE_FFLAGS /* use file_pointer->f_flags to indicate purpose for open() */ CDO_LOCK /* try to lock door if device is opened */ CDO_CHECK_TYPE /* ensure disc type is data if opened for data */h]hXDCDO_AUTO_CLOSE /* try to close tray upon device open() */ CDO_AUTO_EJECT /* try to open tray on last device close() */ CDO_USE_FFLAGS /* use file_pointer->f_flags to indicate purpose for open() */ CDO_LOCK /* try to lock door if device is opened */ CDO_CHECK_TYPE /* ensure disc type is data if opened for data */}hjWsbah}(h]h ]h"]h$]h&]jjuh1jhhhMAhj&hhubh)}(hX The initial value of this register is `CDO_AUTO_CLOSE | CDO_USE_FFLAGS | CDO_LOCK`, reflecting my own view on user interface and software standards. Before you protest, there are two new *ioctl()'s* implemented in `cdrom.c`, that allow you to control the behavior by software. These are::h](h&The initial value of this register is }(hjehhhNhNubj@)}(h,`CDO_AUTO_CLOSE | CDO_USE_FFLAGS | CDO_LOCK`h]h*CDO_AUTO_CLOSE | CDO_USE_FFLAGS | CDO_LOCK}(hjmhhhNhNubah}(h]h ]h"]h$]h&]uh1j?hjeubhi, reflecting my own view on user interface and software standards. Before you protest, there are two new }(hjehhhNhNubjT)}(h *ioctl()'s*h]h ioctl()’s}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjeubh implemented in }(hjehhhNhNubj@)}(h `cdrom.c`h]hcdrom.c}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1j?hjeubh@, that allow you to control the behavior by software. These are:}(hjehhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMGhj&hhubj)}(hCDROM_SET_OPTIONS /* set options specified in (int)arg */ CDROM_CLEAR_OPTIONS /* clear options specified in (int)arg */h]hCDROM_SET_OPTIONS /* set options specified in (int)arg */ CDROM_CLEAR_OPTIONS /* clear options specified in (int)arg */}hjsbah}(h]h ]h"]h$]h&]jjuh1jhhhMMhj&hhubh)}(h}One option needs some more explanation: *CDO_USE_FFLAGS*. In the next newsection we explain what the need for this option is.h](h(One option needs some more explanation: }(hjhhhNhNubjT)}(h*CDO_USE_FFLAGS*h]hCDO_USE_FFLAGS}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubhE. In the next newsection we explain what the need for this option is.}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMPhj&hhubh)}(hA software package `setcd`, available from the Debian distribution and `sunsite.unc.edu`, allows user level control of these flags.h](hA software package }(hjhhhNhNubj@)}(h`setcd`h]hsetcd}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1j?hjubh-, available from the Debian distribution and }(hjhhhNhNubj@)}(h`sunsite.unc.edu`h]hsunsite.unc.edu}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1j?hjubh+, allows user level control of these flags.}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMShj&hhubeh}(h]optionsah ]h"]optionsah$]h&]uh1hhjhhhhhM9ubeh}(h](,standardizing-through-another-software-leveljeh ]h"](,standardizing through another software level cdrom_apieh$]h&]uh1hhhhhhhhKuj }jjsj }jjsjKubh)}(hhh](h)}(h9The need to know the purpose of opening the CD-ROM deviceh]h9The need to know the purpose of opening the CD-ROM device}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjhhhhhMXubh)}(hXTraditionally, Unix devices can be used in two different `modes`, either by reading/writing to the device file, or by issuing controlling commands to the device, by the device's *ioctl()* call. The problem with CD-ROM drives, is that they can be used for two entirely different purposes. One is to mount removable file systems, CD-ROM's, the other is to play audio CD's. Audio commands are implemented entirely through *ioctl()\'s*, presumably because the first implementation (SUN?) has been such. In principle there is nothing wrong with this, but a good control of the `CD player` demands that the device can **always** be opened in order to give the *ioctl* commands, regardless of the state the drive is in.h](h9Traditionally, Unix devices can be used in two different }(hj-hhhNhNubj@)}(h`modes`h]hmodes}(hj5hhhNhNubah}(h]h ]h"]h$]h&]uh1j?hj-ubht, either by reading/writing to the device file, or by issuing controlling commands to the device, by the device’s }(hj-hhhNhNubjT)}(h *ioctl()*h]hioctl()}(hjGhhhNhNubah}(h]h ]h"]h$]h&]uh1jShj-ubh call. The problem with CD-ROM drives, is that they can be used for two entirely different purposes. One is to mount removable file systems, CD-ROM’s, the other is to play audio CD’s. Audio commands are implemented entirely through }(hj-hhhNhNubjT)}(h *ioctl()\'s*h]h ioctl()'s}(hjYhhhNhNubah}(h]h ]h"]h$]h&]uh1jShj-ubh, presumably because the first implementation (SUN?) has been such. In principle there is nothing wrong with this, but a good control of the }(hj-hhhNhNubj@)}(h `CD player`h]h CD player}(hjkhhhNhNubah}(h]h ]h"]h$]h&]uh1j?hj-ubh demands that the device can }(hj-hhhNhNubju)}(h **always**h]halways}(hj}hhhNhNubah}(h]h ]h"]h$]h&]uh1jthj-ubh be opened in order to give the }(hj-hhhNhNubjT)}(h*ioctl*h]hioctl}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShj-ubh3 commands, regardless of the state the drive is in.}(hj-hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMZhjhhubh)}(hXOn the other hand, when used as a removable-media disc drive (what the original purpose of CD-ROM s is) we would like to make sure that the disc drive is ready for operation upon opening the device. In the old scheme, some CD-ROM drivers don't do any integrity checking, resulting in a number of i/o errors reported by the VFS to the kernel when an attempt for mounting a CD-ROM on an empty drive occurs. This is not a particularly elegant way to find out that there is no CD-ROM inserted; it more-or-less looks like the old IBM-PC trying to read an empty floppy drive for a couple of seconds, after which the system complains it can't read from it. Nowadays we can **sense** the existence of a removable medium in a drive, and we believe we should exploit that fact. An integrity check on opening of the device, that verifies the availability of a CD-ROM and its correct type (data), would be desirable.h](hXOn the other hand, when used as a removable-media disc drive (what the original purpose of CD-ROM s is) we would like to make sure that the disc drive is ready for operation upon opening the device. In the old scheme, some CD-ROM drivers don’t do any integrity checking, resulting in a number of i/o errors reported by the VFS to the kernel when an attempt for mounting a CD-ROM on an empty drive occurs. This is not a particularly elegant way to find out that there is no CD-ROM inserted; it more-or-less looks like the old IBM-PC trying to read an empty floppy drive for a couple of seconds, after which the system complains it can’t read from it. Nowadays we can }(hjhhhNhNubju)}(h **sense**h]hsense}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jthjubh the existence of a removable medium in a drive, and we believe we should exploit that fact. An integrity check on opening of the device, that verifies the availability of a CD-ROM and its correct type (data), would be desirable.}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMfhjhhubh)}(hX>These two ways of using a CD-ROM drive, principally for data and secondarily for playing audio discs, have different demands for the behavior of the *open()* call. Audio use simply wants to open the device in order to get a file handle which is needed for issuing *ioctl* commands, while data use wants to open for correct and reliable data transfer. The only way user programs can indicate what their *purpose* of opening the device is, is through the *flags* parameter (see `open(2)`). For CD-ROM devices, these flags aren't implemented (some drivers implement checking for write-related flags, but this is not strictly necessary if the device file has correct permission flags). Most option flags simply don't make sense to CD-ROM devices: *O_CREAT*, *O_NOCTTY*, *O_TRUNC*, *O_APPEND*, and *O_SYNC* have no meaning to a CD-ROM.h](hThese two ways of using a CD-ROM drive, principally for data and secondarily for playing audio discs, have different demands for the behavior of the }(hjhhhNhNubjT)}(h*open()*h]hopen()}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubhk call. Audio use simply wants to open the device in order to get a file handle which is needed for issuing }(hjhhhNhNubjT)}(h*ioctl*h]hioctl}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubh commands, while data use wants to open for correct and reliable data transfer. The only way user programs can indicate what their }(hjhhhNhNubjT)}(h *purpose*h]hpurpose}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubh* of opening the device is, is through the }(hjhhhNhNubjT)}(h*flags*h]hflags}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubh parameter (see }(hjhhhNhNubj@)}(h `open(2)`h]hopen(2)}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1j?hjubhX). For CD-ROM devices, these flags aren’t implemented (some drivers implement checking for write-related flags, but this is not strictly necessary if the device file has correct permission flags). Most option flags simply don’t make sense to CD-ROM devices: }(hjhhhNhNubjT)}(h *O_CREAT*h]hO_CREAT}(hj)hhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubh, }(hjhhhNhNubjT)}(h *O_NOCTTY*h]hO_NOCTTY}(hj;hhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubh, }hjsbjT)}(h *O_TRUNC*h]hO_TRUNC}(hjMhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubh, }hjsbjT)}(h *O_APPEND*h]hO_APPEND}(hj_hhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubh, and }(hjhhhNhNubjT)}(h*O_SYNC*h]hO_SYNC}(hjqhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubh have no meaning to a CD-ROM.}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMuhjhhubh)}(hXWe therefore propose to use the flag *O_NONBLOCK* to indicate that the device is opened just for issuing *ioctl* commands. Strictly, the meaning of *O_NONBLOCK* is that opening and subsequent calls to the device don't cause the calling process to wait. We could interpret this as don't wait until someone has inserted some valid data-CD-ROM. Thus, our proposal of the implementation for the *open()* call for CD-ROM s is:h](h%We therefore propose to use the flag }(hjhhhNhNubjT)}(h *O_NONBLOCK*h]h O_NONBLOCK}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubh8 to indicate that the device is opened just for issuing }(hjhhhNhNubjT)}(h*ioctl*h]hioctl}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubh$ commands. Strictly, the meaning of }(hjhhhNhNubjT)}(h *O_NONBLOCK*h]h O_NONBLOCK}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubh is that opening and subsequent calls to the device don’t cause the calling process to wait. We could interpret this as don’t wait until someone has inserted some valid data-CD-ROM. Thus, our proposal of the implementation for the }(hjhhhNhNubjT)}(h*open()*h]hopen()}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubh call for CD-ROM s is:}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhjhhubj)}(hhh](j)}(hIf no other flags are set than *O_RDONLY*, the device is opened for data transfer, and the return value will be 0 only upon successful initialization of the transfer. The call may even induce some actions on the CD-ROM, such as closing the tray.h]h)}(hIf no other flags are set than *O_RDONLY*, the device is opened for data transfer, and the return value will be 0 only upon successful initialization of the transfer. The call may even induce some actions on the CD-ROM, such as closing the tray.h](hIf no other flags are set than }(hjhhhNhNubjT)}(h *O_RDONLY*h]hO_RDONLY}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubh, the device is opened for data transfer, and the return value will be 0 only upon successful initialization of the transfer. The call may even induce some actions on the CD-ROM, such as closing the tray.}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhjubah}(h]h ]h"]h$]h&]uh1jhjhhhhhNubj)}(hIf the option flag *O_NONBLOCK* is set, opening will always be successful, unless the whole device doesn't exist. The drive will take no actions whatsoever. h]h)}(hIf the option flag *O_NONBLOCK* is set, opening will always be successful, unless the whole device doesn't exist. The drive will take no actions whatsoever.h](hIf the option flag }(hjhhhNhNubjT)}(h *O_NONBLOCK*h]h O_NONBLOCK}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubh is set, opening will always be successful, unless the whole device doesn’t exist. The drive will take no actions whatsoever.}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhj ubah}(h]h ]h"]h$]h&]uh1jhjhhhhhNubeh}(h]h ]h"]h$]h&]j5j6uh1jhhhMhjhhubh)}(hhh](h)}(hAnd what about standards?h]hAnd what about standards?}(hj?hhhNhNubah}(h]h ]h"]h$]h&]uh1hhj<hhhhhMubh)}(hXYou might hesitate to accept this proposal as it comes from the Linux community, and not from some standardizing institute. What about SUN, SGI, HP and all those other Unix and hardware vendors? Well, these companies are in the lucky position that they generally control both the hardware and software of their supported products, and are large enough to set their own standard. They do not have to deal with a dozen or more different, competing hardware configurations\ [#f3]_.h](hXYou might hesitate to accept this proposal as it comes from the Linux community, and not from some standardizing institute. What about SUN, SGI, HP and all those other Unix and hardware vendors? Well, these companies are in the lucky position that they generally control both the hardware and software of their supported products, and are large enough to set their own standard. They do not have to deal with a dozen or more different, competing hardware configurations }(hjMhhhNhNubj)}(h[#f3]_h]h3}(hjUhhhNhNubah}(h]id3ah ]h"]h$]h&]jKjf3jjuh1jhjMjKubh.}(hjMhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhj<hhubj1)}(hXIncidentally, I think that SUN's approach to mounting CD-ROM s is very good in origin: under Solaris a volume-daemon automatically mounts a newly inserted CD-ROM under `/cdrom/**`. In my opinion they should have pushed this further and have **every** CD-ROM on the local area network be mounted at the similar location, i. e., no matter in which particular machine you insert a CD-ROM, it will always appear at the same position in the directory tree, on every system. When I wanted to implement such a user-program for Linux, I came across the differences in behavior of the various drivers, and the need for an *ioctl* informing about media changes. h](j7)}(hhh]h3}(hjshhhNhNubah}(h]h ]h"]h$]h&]uh1j6hjohhhNhNubh)}(hIncidentally, I think that SUN's approach to mounting CD-ROM s is very good in origin: under Solaris a volume-daemon automatically mounts a newly inserted CD-ROM under `/cdrom/**`.h](hIncidentally, I think that SUN’s approach to mounting CD-ROM s is very good in origin: under Solaris a volume-daemon automatically mounts a newly inserted CD-ROM under }(hjhhhNhNubj@)}(h`/cdrom/**`h]h/cdrom/**}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1j?hjubh.}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhjoubh)}(hXIn my opinion they should have pushed this further and have **every** CD-ROM on the local area network be mounted at the similar location, i. e., no matter in which particular machine you insert a CD-ROM, it will always appear at the same position in the directory tree, on every system. When I wanted to implement such a user-program for Linux, I came across the differences in behavior of the various drivers, and the need for an *ioctl* informing about media changes.h](h_info);h]hregister_cdrom(&_info);}hjsbah}(h]h ]h"]h$]h&]jjuh1jhhhMhjhhubh)}(hThis function returns zero upon success, and non-zero upon failure. The structure *_info* should have a pointer to the driver's *_dops*, as in::h](hRThis function returns zero upon success, and non-zero upon failure. The structure }(hjhhhNhNubjT)}(h*_info*h]h _info}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubh) should have a pointer to the driver’s }(hjhhhNhNubjT)}(h*_dops*h]h _dops}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubh, as in:}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhjhhubj)}(hOstruct cdrom_device_info _info = { _dops; ... }h]hOstruct cdrom_device_info _info = { _dops; ... }}hj sbah}(h]h ]h"]h$]h&]jjuh1jhhhMhjhhubh)}(hNote that a driver must have one static structure, *_dops*, while it may have as many structures *_info* as there are minor devices active. *Register_cdrom()* builds a linked list from these.h](h3Note that a driver must have one static structure, }(hjhhhNhNubjT)}(h*_dops*h]h _dops}(hj"hhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubh', while it may have as many structures }(hjhhhNhNubjT)}(h*_info*h]h _info}(hj4hhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubh$ as there are minor devices active. }(hjhhhNhNubjT)}(h*Register_cdrom()*h]hRegister_cdrom()}(hjFhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubh! builds a linked list from these.}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhjhhubj)}(h4void unregister_cdrom(struct cdrom_device_info *cdi)h]h4void unregister_cdrom(struct cdrom_device_info *cdi)}hj^sbah}(h]h ]h"]h$]h&]jjuh1jhhhMhjhhubh)}(hX=Unregistering device *cdi* with minor number *MINOR(cdi->dev)* removes the minor device from the list. If it was the last registered minor for the low-level driver, this disconnects the registered device-operation routines from the CD-ROM interface. This function returns zero upon success, and non-zero upon failure.h](hUnregistering device }(hjlhhhNhNubjT)}(h*cdi*h]hcdi}(hjthhhNhNubah}(h]h ]h"]h$]h&]uh1jShjlubh with minor number }(hjlhhhNhNubjT)}(h*MINOR(cdi->dev)*h]hMINOR(cdi->dev)}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjlubh removes the minor device from the list. If it was the last registered minor for the low-level driver, this disconnects the registered device-operation routines from the CD-ROM interface. This function returns zero upon success, and non-zero upon failure.}(hjlhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhjhhubj)}(h3int cdrom_open(struct inode * ip, struct file * fp)h]h3int cdrom_open(struct inode * ip, struct file * fp)}hjsbah}(h]h ]h"]h$]h&]jjuh1jhhhM hjhhubh)}(hXThis function is not called directly by the low-level drivers, it is listed in the standard *cdrom_fops*. If the VFS opens a file, this function becomes active. A strategy is implemented in this routine, taking care of all capabilities and options that are set in the *cdrom_device_ops* connected to the device. Then, the program flow is transferred to the device_dependent *open()* call.h](h\This function is not called directly by the low-level drivers, it is listed in the standard }(hjhhhNhNubjT)}(h *cdrom_fops*h]h cdrom_fops}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubh. If the VFS opens a file, this function becomes active. A strategy is implemented in this routine, taking care of all capabilities and options that are set in the }(hjhhhNhNubjT)}(h*cdrom_device_ops*h]hcdrom_device_ops}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubhX connected to the device. Then, the program flow is transferred to the device_dependent }(hjhhhNhNubjT)}(h*open()*h]hopen()}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubh call.}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhjhhubj)}(h5void cdrom_release(struct inode *ip, struct file *fp)h]h5void cdrom_release(struct inode *ip, struct file *fp)}hjsbah}(h]h ]h"]h$]h&]jjuh1jhhhMhjhhubh)}(hThis function implements the reverse-logic of *cdrom_open()*, and then calls the device-dependent *release()* routine. When the use-count has reached 0, the allocated buffers are flushed by calls to *sync_dev(dev)* and *invalidate_buffers(dev)*.h](h.This function implements the reverse-logic of }(hjhhhNhNubjT)}(h*cdrom_open()*h]h cdrom_open()}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubh&, and then calls the device-dependent }(hjhhhNhNubjT)}(h *release()*h]h release()}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubhZ routine. When the use-count has reached 0, the allocated buffers are flushed by calls to }(hjhhhNhNubjT)}(h*sync_dev(dev)*h]h sync_dev(dev)}(hj*hhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubh and }(hjhhhNhNubjT)}(h*invalidate_buffers(dev)*h]hinvalidate_buffers(dev)}(hj<hhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubh.}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhjhhubj)}(h.. _cdrom_ioctl:h]h}(h]h ]h"]h$]h&]j cdrom-ioctluh1jhMhjhhhhjKubj)}(hgint cdrom_ioctl(struct inode *ip, struct file *fp, unsigned int cmd, unsigned long arg)h]hgint cdrom_ioctl(struct inode *ip, struct file *fp, unsigned int cmd, unsigned long arg)}hj_sbah}(h]j^ah ]h"] cdrom_ioctlah$]h&]jjuh1jhhhM#hjhhj }jkjTsj }j^jTsjKubh)}(hX{This function handles all the standard *ioctl* requests for CD-ROM devices in a uniform way. The different calls fall into three categories: *ioctl()'s* that can be directly implemented by device operations, ones that are routed through the call *audio_ioctl()*, and the remaining ones, that are presumable device-dependent. Generally, a negative return value indicates an error.h](h'This function handles all the standard }(hjphhhNhNubjT)}(h*ioctl*h]hioctl}(hjxhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjpubh_ requests for CD-ROM devices in a uniform way. The different calls fall into three categories: }(hjphhhNhNubjT)}(h *ioctl()'s*h]h ioctl()’s}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjpubh^ that can be directly implemented by device operations, ones that are routed through the call }(hjphhhNhNubjT)}(h*audio_ioctl()*h]h audio_ioctl()}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjpubhv, and the remaining ones, that are presumable device-dependent. Generally, a negative return value indicates an error.}(hjphhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhM&hjhhubh)}(hhh](h)}(h Directly implemented *ioctl()'s*h](hDirectly implemented }(hjhhhNhNubjT)}(h *ioctl()'s*h]h ioctl()’s}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubeh}(h]h ]h"]h$]h&]uh1hhjhhhhhM.ubh)}(hThe following `old` CD-ROM *ioctl()*\ 's are implemented by directly calling device-operations in *cdrom_device_ops*, if implemented and not masked:h](hThe following }(hjhhhNhNubj@)}(h`old`h]hold}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1j?hjubh CD-ROM }(hjhhhNhNubjT)}(h *ioctl()*h]hioctl()}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubh@ ‘s are implemented by directly calling device-operations in }(hjhhhNhNubjT)}(h*cdrom_device_ops*h]hcdrom_device_ops}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubh , if implemented and not masked:}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhM0hjhhubj)}(hhh](j)}(h:`CDROMMULTISESSION` Requests the last session on a CD-ROM.h](j)}(h`CDROMMULTISESSION`h]j@)}(hj h]hCDROMMULTISESSION}(hj"hhhNhNubah}(h]h ]h"]h$]h&]uh1j?hjubah}(h]h ]h"]h$]h&]uh1jhhhM4hjubj)}(hhh]h)}(h&Requests the last session on a CD-ROM.h]h&Requests the last session on a CD-ROM.}(hj8hhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhM5hj5ubah}(h]h ]h"]h$]h&]uh1jhjubeh}(h]h ]h"]h$]h&]uh1jhhhM4hjubj)}(h`CDROMEJECT` Open tray.h](j)}(h `CDROMEJECT`h]j@)}(hjXh]h CDROMEJECT}(hjZhhhNhNubah}(h]h ]h"]h$]h&]uh1j?hjVubah}(h]h ]h"]h$]h&]uh1jhhhM6hjRubj)}(hhh]h)}(h Open tray.h]h Open tray.}(hjphhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhM7hjmubah}(h]h ]h"]h$]h&]uh1jhjRubeh}(h]h ]h"]h$]h&]uh1jhhhM6hjhhubj)}(h`CDROMCLOSETRAY` Close tray.h](j)}(h`CDROMCLOSETRAY`h]j@)}(hjh]hCDROMCLOSETRAY}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1j?hjubah}(h]h ]h"]h$]h&]uh1jhhhM8hjubj)}(hhh]h)}(h Close tray.h]h Close tray.}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhM9hjubah}(h]h ]h"]h$]h&]uh1jhjubeh}(h]h ]h"]h$]h&]uh1jhhhM8hjhhubj)}(h`CDROMEJECT_SW` If *arg\not=0*, set behavior to auto-close (close tray on first open) and auto-eject (eject on last release), otherwise set behavior to non-moving on *open()* and *release()* calls.h](j)}(h`CDROMEJECT_SW`h]j@)}(hjh]h CDROMEJECT_SW}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1j?hjubah}(h]h ]h"]h$]h&]uh1jhhhM<hjubj)}(hhh]h)}(hIf *arg\not=0*, set behavior to auto-close (close tray on first open) and auto-eject (eject on last release), otherwise set behavior to non-moving on *open()* and *release()* calls.h](hIf }(hjhhhNhNubjT)}(h *arg\not=0*h]h argnot=0}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubh, set behavior to auto-close (close tray on first open) and auto-eject (eject on last release), otherwise set behavior to non-moving on }(hjhhhNhNubjT)}(h*open()*h]hopen()}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubh and }(hjhhhNhNubjT)}(h *release()*h]h release()}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubh calls.}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhM;hjubah}(h]h ]h"]h$]h&]uh1jhjubeh}(h]h ]h"]h$]h&]uh1jhhhM<hjhhubj)}(h8`CDROM_GET_MCN` Get the Media Catalog Number from a CD. h](j)}(h`CDROM_GET_MCN`h]j@)}(hj6h]h CDROM_GET_MCN}(hj8hhhNhNubah}(h]h ]h"]h$]h&]uh1j?hj4ubah}(h]h ]h"]h$]h&]uh1jhhhM?hj0ubj)}(hhh]h)}(h'Get the Media Catalog Number from a CD.h]h'Get the Media Catalog Number from a CD.}(hjNhhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhM?hjKubah}(h]h ]h"]h$]h&]uh1jhj0ubeh}(h]h ]h"]h$]h&]uh1jhhhM?hjhhubeh}(h]h ]h"]h$]h&]uh1jhjhhhhhNubeh}(h]directly-implemented-ioctl-sah ]h"]directly implemented ioctl()'sah$]h&]uh1hhjhhhhhM.ubh)}(hhh](h)}(h'*Ioctl*s routed through *audio_ioctl()*h]jT)}(hj{h]h%Ioctl*s routed through *audio_ioctl()}(hj}hhhNhNubah}(h]h ]h"]h$]h&]uh1jShjyubah}(h]h ]h"]h$]h&]uh1hhjvhhhhhMBubh)}(hThe following set of *ioctl()'s* are all implemented through a call to the *cdrom_fops* function *audio_ioctl()*. Memory checks and allocation are performed in *cdrom_ioctl()*, and also sanitization of address format (*CDROM_LBA*/*CDROM_MSF*) is done.h](hThe following set of }(hjhhhNhNubjT)}(h *ioctl()'s*h]h ioctl()’s}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubh+ are all implemented through a call to the }(hjhhhNhNubjT)}(h *cdrom_fops*h]h cdrom_fops}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubh function }(hjhhhNhNubjT)}(h*audio_ioctl()*h]h audio_ioctl()}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubh0. Memory checks and allocation are performed in }(hjhhhNhNubjT)}(h*cdrom_ioctl()*h]h cdrom_ioctl()}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubh+, and also sanitization of address format (}(hjhhhNhNubjT)}(h *CDROM_LBA*h]h CDROM_LBA}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubh/}(hjhhhNhNubjT)}(h *CDROM_MSF*h]h CDROM_MSF}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubh ) is done.}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMDhjvhhubj)}(hhh](j)}(hW`CDROMSUBCHNL` Get sub-channel data in argument *arg* of type `struct cdrom_subchnl *`.h](j)}(h`CDROMSUBCHNL`h]j@)}(hjh]h CDROMSUBCHNL}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1j?hjubah}(h]h ]h"]h$]h&]uh1jhhhMJhj ubj)}(hhh]h)}(hHGet sub-channel data in argument *arg* of type `struct cdrom_subchnl *`.h](h!Get sub-channel data in argument }(hj+hhhNhNubjT)}(h*arg*h]harg}(hj3hhhNhNubah}(h]h ]h"]h$]h&]uh1jShj+ubh of type }(hj+hhhNhNubj@)}(h`struct cdrom_subchnl *`h]hstruct cdrom_subchnl *}(hjEhhhNhNubah}(h]h ]h"]h$]h&]uh1j?hj+ubh.}(hj+hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMJhj(ubah}(h]h ]h"]h$]h&]uh1jhj ubeh}(h]h ]h"]h$]h&]uh1jhhhMJhj ubj)}(hZ`CDROMREADTOCHDR` Read Table of Contents header, in *arg* of type `struct cdrom_tochdr *`.h](j)}(h`CDROMREADTOCHDR`h]j@)}(hjoh]hCDROMREADTOCHDR}(hjqhhhNhNubah}(h]h ]h"]h$]h&]uh1j?hjmubah}(h]h ]h"]h$]h&]uh1jhhhMMhjiubj)}(hhh]h)}(hHRead Table of Contents header, in *arg* of type `struct cdrom_tochdr *`.h](h"Read Table of Contents header, in }(hjhhhNhNubjT)}(h*arg*h]harg}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubh of type }(hjhhhNhNubj@)}(h`struct cdrom_tochdr *`h]hstruct cdrom_tochdr *}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1j?hjubh.}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMMhjubah}(h]h ]h"]h$]h&]uh1jhjiubeh}(h]h ]h"]h$]h&]uh1jhhhMMhj hhubj)}(hu`CDROMREADTOCENTRY` Read a Table of Contents entry in *arg* and specified by *arg* of type `struct cdrom_tocentry *`.h](j)}(h`CDROMREADTOCENTRY`h]j@)}(hjh]hCDROMREADTOCENTRY}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1j?hjubah}(h]h ]h"]h$]h&]uh1jhhhMPhjubj)}(hhh]h)}(haRead a Table of Contents entry in *arg* and specified by *arg* of type `struct cdrom_tocentry *`.h](h"Read a Table of Contents entry in }(hjhhhNhNubjT)}(h*arg*h]harg}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubh and specified by }(hjhhhNhNubjT)}(h*arg*h]harg}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubh of type }(hjhhhNhNubj@)}(h`struct cdrom_tocentry *`h]hstruct cdrom_tocentry *}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1j?hjubh.}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMPhjubah}(h]h ]h"]h$]h&]uh1jhjubeh}(h]h ]h"]h$]h&]uh1jhhhMPhj hhubj)}(h~`CDROMPLAYMSF` Play audio fragment specified in Minute, Second, Frame format, delimited by *arg* of type `struct cdrom_msf *`.h](j)}(h`CDROMPLAYMSF`h]j@)}(hj9h]h CDROMPLAYMSF}(hj;hhhNhNubah}(h]h ]h"]h$]h&]uh1j?hj7ubah}(h]h ]h"]h$]h&]uh1jhhhMShj3ubj)}(hhh]h)}(hoPlay audio fragment specified in Minute, Second, Frame format, delimited by *arg* of type `struct cdrom_msf *`.h](hLPlay audio fragment specified in Minute, Second, Frame format, delimited by }(hjQhhhNhNubjT)}(h*arg*h]harg}(hjYhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjQubh of type }(hjQhhhNhNubj@)}(h`struct cdrom_msf *`h]hstruct cdrom_msf *}(hjkhhhNhNubah}(h]h ]h"]h$]h&]uh1j?hjQubh.}(hjQhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMShjNubah}(h]h ]h"]h$]h&]uh1jhj3ubeh}(h]h ]h"]h$]h&]uh1jhhhMShj hhubj)}(hk`CDROMPLAYTRKIND` Play audio fragment in track-index format delimited by *arg* of type `struct cdrom_ti *`.h](j)}(h`CDROMPLAYTRKIND`h]j@)}(hjh]hCDROMPLAYTRKIND}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1j?hjubah}(h]h ]h"]h$]h&]uh1jhhhMVhjubj)}(hhh]h)}(hYPlay audio fragment in track-index format delimited by *arg* of type `struct cdrom_ti *`.h](h7Play audio fragment in track-index format delimited by }(hjhhhNhNubjT)}(h*arg*h]harg}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjubh of type }(hjhhhNhNubj@)}(h`struct cdrom_ti *`h]hstruct cdrom_ti *}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1j?hjubh.}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMVhjubah}(h]h ]h"]h$]h&]uh1jhjubeh}(h]h ]h"]h$]h&]uh1jhhhMVhj hhubj)}(hN`CDROMVOLCTRL` Set volume specified by *arg* of type `struct cdrom_volctrl *`.h](j)}(h`CDROMVOLCTRL`h]j@)}(hjh]h CDROMVOLCTRL}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1j?hjubah}(h]h ]h"]h$]h&]uh1jhhhMXhjubj)}(hhh]h)}(h?Set volume specified by *arg* of type `struct cdrom_volctrl *`.h](hSet volume specified by }(hj hhhNhNubjT)}(h*arg*h]harg}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jShj ubh of type }(hj hhhNhNubj@)}(h`struct cdrom_volctrl *`h]hstruct cdrom_volctrl *}(hj#hhhNhNubah}(h]h ]h"]h$]h&]uh1j?hj ubh.}(hj hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMYhjubah}(h]h ]h"]h$]h&]uh1jhjubeh}(h]h ]h"]h$]h&]uh1jhhhMXhj hhubj)}(hJ`CDROMVOLREAD` Read volume into by *arg* of type `struct cdrom_volctrl *`.h](j)}(h`CDROMVOLREAD`h]j@)}(hjMh]h CDROMVOLREAD}(hjOhhhNhNubah}(h]h ]h"]h$]h&]uh1j?hjKubah}(h]h ]h"]h$]h&]uh1jhhhMZhjGubj)}(hhh]h)}(h;Read volume into by *arg* of type `struct cdrom_volctrl *`.h](hRead volume into by }(hjehhhNhNubjT)}(h*arg*h]harg}(hjmhhhNhNubah}(h]h ]h"]h$]h&]uh1jShjeubh of type }(hjehhhNhNubj@)}(h`struct cdrom_volctrl *`h]hstruct cdrom_volctrl *}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1j?hjeubh.}(hjehhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhM[hjbubah}(h]h ]h"]h$]h&]uh1jhjGubeh}(h]h ]h"]h$]h&]uh1jhhhMZhj hhubj)}(h`CDROMSTART` Spin up disc.h](j)}(h `CDROMSTART`h]j@)}(hjh]h CDROMSTART}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1j?hjubah}(h]h ]h"]h$]h&]uh1jhhhM\hjubj)}(hhh]h)}(h Spin up disc.h]h Spin up disc.}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhM]hjubah}(h]h ]h"]h$]h&]uh1jhjubeh}(h]h ]h"]h$]h&]uh1jhhhM\hj hhubj)}(h,`CDROMSTOP` Stop playback of audio fragment.h](j)}(h `CDROMSTOP`h]j@)}(hjh]h CDROMSTOP}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1j?hjubah}(h]h ]h"]h$]h&]uh1jhhhM^hjubj)}(hhh]h)}(h Stop playback of audio fragment.h]h Stop playback of audio fragment.}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhM_hjubah}(h]h ]h"]h$]h&]uh1jhjubeh}(h]h ]h"]h$]h&]uh1jhhhM^hj hhubj)}(h.`CDROMPAUSE` Pause playback of audio fragment.h](j)}(h `CDROMPAUSE`h]j@)}(hj h]h CDROMPAUSE}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1j?hj ubah}(h]h ]h"]h$]h&]uh1jhhhM`hj ubj)}(hhh]h)}(h!Pause playback of audio fragment.h]h!Pause playback of audio fragment.}(hj1 hhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhMahj. ubah}(h]h ]h"]h$]h&]uh1jhj ubeh}(h]h ]h"]h$]h&]uh1jhhhM`hj hhubj)}(h`CDROMRESUME` Resume playing. h](j)}(h `CDROMRESUME`h]j@)}(hjQ h]h CDROMRESUME}(hjS hhhNhNubah}(h]h ]h"]h$]h&]uh1j?hjO ubah}(h]h ]h"]h$]h&]uh1jhhhMchjK ubj)}(hhh]h)}(hResume playing.h]hResume playing.}(hji hhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhMchjf ubah}(h]h ]h"]h$]h&]uh1jhjK ubeh}(h]h ]h"]h$]h&]uh1jhhhMchj hhubeh}(h]h ]h"]h$]h&]uh1jhjvhhhhhNubeh}(h]"ioctl-s-routed-through-audio-ioctlah ]h"]%ioctl*s routed through *audio_ioctl()ah$]h&]uh1hhjhhhhhMBubh)}(hhh](h)}(hNew *ioctl()'s* in `cdrom.c`h](hNew }(hj hhhNhNubjT)}(h *ioctl()'s*h]h ioctl()’s}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1jShj ubh in }(hj hhhNhNubj@)}(h `cdrom.c`h]hcdrom.c}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1j?hj ubeh}(h]h ]h"]h$]h&]uh1hhj hhhhhMfubh)}(hThe following *ioctl()'s* have been introduced to allow user programs to control the behavior of individual CD-ROM devices. New *ioctl* commands can be identified by the underscores in their names.h](hThe following }(hj hhhNhNubjT)}(h *ioctl()'s*h]h ioctl()’s}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1jShj ubhg have been introduced to allow user programs to control the behavior of individual CD-ROM devices. New }(hj hhhNhNubjT)}(h*ioctl*h]hioctl}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1jShj ubh> commands can be identified by the underscores in their names.}(hj hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhhj hhubj)}(hhh](j)}(h`CDROM_SET_OPTIONS` Set options specified by *arg*. Returns the option flag register after modification. Use *arg = \rm0* for reading the current flags.h](j)}(h`CDROM_SET_OPTIONS`h]j@)}(hj h]hCDROM_SET_OPTIONS}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1j?hj ubah}(h]h ]h"]h$]h&]uh1jhhhMmhj ubj)}(hhh]h)}(hSet options specified by *arg*. Returns the option flag register after modification. Use *arg = \rm0* for reading the current flags.h](hSet options specified by }(hj!hhhNhNubjT)}(h*arg*h]harg}(hj!hhhNhNubah}(h]h ]h"]h$]h&]uh1jShj!ubh;. Returns the option flag register after modification. Use }(hj!hhhNhNubjT)}(h *arg = \rm0*h]h arg = rm0}(hj/!hhhNhNubah}(h]h ]h"]h$]h&]uh1jShj!ubh for reading the current flags.}(hj!hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMmhj!ubah}(h]h ]h"]h$]h&]uh1jhj ubeh}(h]h ]h"]h$]h&]uh1jhhhMmhj ubj)}(hl`CDROM_CLEAR_OPTIONS` Clear options specified by *arg*. Returns the option flag register after modification.h](j)}(h`CDROM_CLEAR_OPTIONS`h]j@)}(hjY!h]hCDROM_CLEAR_OPTIONS}(hj[!hhhNhNubah}(h]h ]h"]h$]h&]uh1j?hjW!ubah}(h]h ]h"]h$]h&]uh1jhhhMphjS!ubj)}(hhh]h)}(hVClear options specified by *arg*. Returns the option flag register after modification.h](hClear options specified by }(hjq!hhhNhNubjT)}(h*arg*h]harg}(hjy!hhhNhNubah}(h]h ]h"]h$]h&]uh1jShjq!ubh6. Returns the option flag register after modification.}(hjq!hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMphjn!ubah}(h]h ]h"]h$]h&]uh1jhjS!ubeh}(h]h ]h"]h$]h&]uh1jhhhMphj hhubj)}(hXh`CDROM_SELECT_SPEED` Select head-rate speed of disc specified as by *arg* in units of standard cdrom speed (176\,kB/sec raw data or 150kB/sec file system data). The value 0 means `auto-select`, i. e., play audio discs at real time and data discs at maximum speed. The value *arg* is checked against the maximum head rate of the drive found in the *cdrom_dops*.h](j)}(h`CDROM_SELECT_SPEED`h]j@)}(hj!h]hCDROM_SELECT_SPEED}(hj!hhhNhNubah}(h]h ]h"]h$]h&]uh1j?hj!ubah}(h]h ]h"]h$]h&]uh1jhhhMwhj!ubj)}(hhh]h)}(hXSSelect head-rate speed of disc specified as by *arg* in units of standard cdrom speed (176\,kB/sec raw data or 150kB/sec file system data). The value 0 means `auto-select`, i. e., play audio discs at real time and data discs at maximum speed. The value *arg* is checked against the maximum head rate of the drive found in the *cdrom_dops*.h](h/Select head-rate speed of disc specified as by }(hj!hhhNhNubjT)}(h*arg*h]harg}(hj!hhhNhNubah}(h]h ]h"]h$]h&]uh1jShj!ubhj in units of standard cdrom speed (176,kB/sec raw data or 150kB/sec file system data). The value 0 means }(hj!hhhNhNubj@)}(h `auto-select`h]h auto-select}(hj!hhhNhNubah}(h]h ]h"]h$]h&]uh1j?hj!ubhR, i. e., play audio discs at real time and data discs at maximum speed. The value }(hj!hhhNhNubjT)}(h*arg*h]harg}(hj!hhhNhNubah}(h]h ]h"]h$]h&]uh1jShj!ubhD is checked against the maximum head rate of the drive found in the }(hj!hhhNhNubjT)}(h *cdrom_dops*h]h cdrom_dops}(hj!hhhNhNubah}(h]h ]h"]h$]h&]uh1jShj!ubh.}(hj!hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMshj!ubah}(h]h ]h"]h$]h&]uh1jhj!ubeh}(h]h ]h"]h$]h&]uh1jhhhMwhj hhubj)}(h`CDROM_SELECT_DISC` Select disc numbered *arg* from a juke-box. First disc is numbered 0. The number *arg* is checked against the maximum number of discs in the juke-box found in the *cdrom_dops*.h](j)}(h`CDROM_SELECT_DISC`h]j@)}(hj#"h]hCDROM_SELECT_DISC}(hj%"hhhNhNubah}(h]h ]h"]h$]h&]uh1j?hj!"ubah}(h]h ]h"]h$]h&]uh1jhhhM|hj"ubj)}(hhh](h)}(h+Select disc numbered *arg* from a juke-box.h](hSelect disc numbered }(hj;"hhhNhNubjT)}(h*arg*h]harg}(hjC"hhhNhNubah}(h]h ]h"]h$]h&]uh1jShj;"ubh from a juke-box.}(hj;"hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMzhj8"ubh)}(hFirst disc is numbered 0. The number *arg* is checked against the maximum number of discs in the juke-box found in the *cdrom_dops*.h](h%First disc is numbered 0. The number }(hj["hhhNhNubjT)}(h*arg*h]harg}(hjc"hhhNhNubah}(h]h ]h"]h$]h&]uh1jShj["ubhM is checked against the maximum number of discs in the juke-box found in the }(hj["hhhNhNubjT)}(h *cdrom_dops*h]h cdrom_dops}(hju"hhhNhNubah}(h]h ]h"]h$]h&]uh1jShj["ubh.}(hj["hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhM|hj8"ubeh}(h]h ]h"]h$]h&]uh1jhj"ubeh}(h]h ]h"]h$]h&]uh1jhhhM|hj hhubj)}(hX`CDROM_MEDIA_CHANGED` Returns 1 if a disc has been changed since the last call. For juke-boxes, an extra argument *arg* specifies the slot for which the information is given. The special value *CDSL_CURRENT* requests that information about the currently selected slot be returned.h](j)}(h`CDROM_MEDIA_CHANGED`h]j@)}(hj"h]hCDROM_MEDIA_CHANGED}(hj"hhhNhNubah}(h]h ]h"]h$]h&]uh1j?hj"ubah}(h]h ]h"]h$]h&]uh1jhhhMhj"ubj)}(hhh]h)}(hXReturns 1 if a disc has been changed since the last call. For juke-boxes, an extra argument *arg* specifies the slot for which the information is given. The special value *CDSL_CURRENT* requests that information about the currently selected slot be returned.h](h\Returns 1 if a disc has been changed since the last call. For juke-boxes, an extra argument }(hj"hhhNhNubjT)}(h*arg*h]harg}(hj"hhhNhNubah}(h]h ]h"]h$]h&]uh1jShj"ubhJ specifies the slot for which the information is given. The special value }(hj"hhhNhNubjT)}(h*CDSL_CURRENT*h]h CDSL_CURRENT}(hj"hhhNhNubah}(h]h ]h"]h$]h&]uh1jShj"ubhI requests that information about the currently selected slot be returned.}(hj"hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhj"ubah}(h]h ]h"]h$]h&]uh1jhj"ubeh}(h]h ]h"]h$]h&]uh1jhhhMhj hhubj)}(hXB`CDROM_TIMED_MEDIA_CHANGE` Checks whether the disc has been changed since a user supplied time and returns the time of the last disc change. *arg* is a pointer to a *cdrom_timed_media_change_info* struct. *arg->last_media_change* may be set by calling code to signal the timestamp of the last known media change (by the caller). Upon successful return, this ioctl call will set *arg->last_media_change* to the latest media change timestamp (in ms) known by the kernel/driver and set *arg->has_changed* to 1 if that timestamp is more recent than the timestamp set by the caller.h](j)}(h`CDROM_TIMED_MEDIA_CHANGE`h]j@)}(hj"h]hCDROM_TIMED_MEDIA_CHANGE}(hj"hhhNhNubah}(h]h ]h"]h$]h&]uh1j?hj"ubah}(h]h ]h"]h$]h&]uh1jhhhMhj"ubj)}(hhh](h)}(hqChecks whether the disc has been changed since a user supplied time and returns the time of the last disc change.h]hqChecks whether the disc has been changed since a user supplied time and returns the time of the last disc change.}(hj#hhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhMhj#ubh)}(hX*arg* is a pointer to a *cdrom_timed_media_change_info* struct. *arg->last_media_change* may be set by calling code to signal the timestamp of the last known media change (by the caller). Upon successful return, this ioctl call will set *arg->last_media_change* to the latest media change timestamp (in ms) known by the kernel/driver and set *arg->has_changed* to 1 if that timestamp is more recent than the timestamp set by the caller.h](jT)}(h*arg*h]harg}(hj%#hhhNhNubah}(h]h ]h"]h$]h&]uh1jShj!#ubh is a pointer to a }(hj!#hhhNhNubjT)}(h*cdrom_timed_media_change_info*h]hcdrom_timed_media_change_info}(hj7#hhhNhNubah}(h]h ]h"]h$]h&]uh1jShj!#ubh struct. }(hj!#hhhNhNubjT)}(h*arg->last_media_change*h]harg->last_media_change}(hjI#hhhNhNubah}(h]h ]h"]h$]h&]uh1jShj!#ubh may be set by calling code to signal the timestamp of the last known media change (by the caller). Upon successful return, this ioctl call will set }(hj!#hhhNhNubjT)}(h*arg->last_media_change*h]harg->last_media_change}(hj[#hhhNhNubah}(h]h ]h"]h$]h&]uh1jShj!#ubhQ to the latest media change timestamp (in ms) known by the kernel/driver and set }(hj!#hhhNhNubjT)}(h*arg->has_changed*h]harg->has_changed}(hjm#hhhNhNubah}(h]h ]h"]h$]h&]uh1jShj!#ubhL to 1 if that timestamp is more recent than the timestamp set by the caller.}(hj!#hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhj#ubeh}(h]h ]h"]h$]h&]uh1jhj"ubeh}(h]h ]h"]h$]h&]uh1jhhhMhj hhubj)}(hX`CDROM_DRIVE_STATUS` Returns the status of the drive by a call to *drive_status()*. Return values are defined in cdrom_drive_status_. Note that this call doesn't return information on the current playing activity of the drive; this can be polled through an *ioctl* call to *CDROMSUBCHNL*. For juke-boxes, an extra argument *arg* specifies the slot for which (possibly limited) information is given. The special value *CDSL_CURRENT* requests that information about the currently selected slot be returned.h](j)}(h`CDROM_DRIVE_STATUS`h]j@)}(hj#h]hCDROM_DRIVE_STATUS}(hj#hhhNhNubah}(h]h ]h"]h$]h&]uh1j?hj#ubah}(h]h ]h"]h$]h&]uh1jhhhMhj#ubj)}(hhh]h)}(hXReturns the status of the drive by a call to *drive_status()*. Return values are defined in cdrom_drive_status_. Note that this call doesn't return information on the current playing activity of the drive; this can be polled through an *ioctl* call to *CDROMSUBCHNL*. For juke-boxes, an extra argument *arg* specifies the slot for which (possibly limited) information is given. The special value *CDSL_CURRENT* requests that information about the currently selected slot be returned.h](h-Returns the status of the drive by a call to }(hj#hhhNhNubjT)}(h*drive_status()*h]hdrive_status()}(hj#hhhNhNubah}(h]h ]h"]h$]h&]uh1jShj#ubh. Return values are defined in }(hj#hhhNhNubh)}(hcdrom_drive_status_h]hcdrom_drive_status}(hj#hhhNhNubah}(h]h ]h"]h$]h&]namecdrom_drive_statusjj uh1hhj#jKubh. Note that this call doesn’t return information on the current playing activity of the drive; this can be polled through an }(hj#hhhNhNubjT)}(h*ioctl*h]hioctl}(hj#hhhNhNubah}(h]h ]h"]h$]h&]uh1jShj#ubh call to }(hj#hhhNhNubjT)}(h*CDROMSUBCHNL*h]h CDROMSUBCHNL}(hj#hhhNhNubah}(h]h ]h"]h$]h&]uh1jShj#ubh$. For juke-boxes, an extra argument }(hj#hhhNhNubjT)}(h*arg*h]harg}(hj$hhhNhNubah}(h]h ]h"]h$]h&]uh1jShj#ubhY specifies the slot for which (possibly limited) information is given. The special value }(hj#hhhNhNubjT)}(h*CDSL_CURRENT*h]h CDSL_CURRENT}(hj$hhhNhNubah}(h]h ]h"]h$]h&]uh1jShj#ubhI requests that information about the currently selected slot be returned.}(hj#hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhj#ubah}(h]h ]h"]h$]h&]uh1jhj#ubeh}(h]h ]h"]h$]h&]uh1jhhhMhj hhubj)}(hX7`CDROM_DISC_STATUS` Returns the type of the disc currently in the drive. It should be viewed as a complement to *CDROM_DRIVE_STATUS*. This *ioctl* can provide *some* information about the current disc that is inserted in the drive. This functionality used to be implemented in the low level drivers, but is now carried out entirely in Uniform CD-ROM Driver. The history of development of the CD's use as a carrier medium for various digital information has lead to many different disc types. This *ioctl* is useful only in the case that CDs have \emph {only one} type of data on them. While this is often the case, it is also very common for CDs to have some tracks with data, and some tracks with audio. Because this is an existing interface, rather than fixing this interface by changing the assumptions it was made under, thereby breaking all user applications that use this function, the Uniform CD-ROM Driver implements this *ioctl* as follows: If the CD in question has audio tracks on it, and it has absolutely no CD-I, XA, or data tracks on it, it will be reported as *CDS_AUDIO*. If it has both audio and data tracks, it will return *CDS_MIXED*. If there are no audio tracks on the disc, and if the CD in question has any CD-I tracks on it, it will be reported as *CDS_XA_2_2*. Failing that, if the CD in question has any XA tracks on it, it will be reported as *CDS_XA_2_1*. Finally, if the CD in question has any data tracks on it, it will be reported as a data CD (*CDS_DATA_1*). This *ioctl* can return:: CDS_NO_INFO /* no information available */ CDS_NO_DISC /* no disc is inserted, or tray is opened */ CDS_AUDIO /* Audio disc (2352 audio bytes/frame) */ CDS_DATA_1 /* data disc, mode 1 (2048 user bytes/frame) */ CDS_XA_2_1 /* mixed data (XA), mode 2, form 1 (2048 user bytes) */ CDS_XA_2_2 /* mixed data (XA), mode 2, form 1 (2324 user bytes) */ CDS_MIXED /* mixed audio/data disc */ For some information concerning frame layout of the various disc types, see a recent version of `cdrom.h`. h](j)}(h`CDROM_DISC_STATUS`h]j@)}(hj=$h]hCDROM_DISC_STATUS}(hj?$hhhNhNubah}(h]h ]h"]h$]h&]uh1j?hj;$ubah}(h]h ]h"]h$]h&]uh1jhhhMhj7$ubj)}(hhh](h)}(hXQReturns the type of the disc currently in the drive. It should be viewed as a complement to *CDROM_DRIVE_STATUS*. This *ioctl* can provide *some* information about the current disc that is inserted in the drive. This functionality used to be implemented in the low level drivers, but is now carried out entirely in Uniform CD-ROM Driver.h](h\Returns the type of the disc currently in the drive. It should be viewed as a complement to }(hjU$hhhNhNubjT)}(h*CDROM_DRIVE_STATUS*h]hCDROM_DRIVE_STATUS}(hj]$hhhNhNubah}(h]h ]h"]h$]h&]uh1jShjU$ubh. This }(hjU$hhhNhNubjT)}(h*ioctl*h]hioctl}(hjo$hhhNhNubah}(h]h ]h"]h$]h&]uh1jShjU$ubh can provide }(hjU$hhhNhNubjT)}(h*some*h]hsome}(hj$hhhNhNubah}(h]h ]h"]h$]h&]uh1jShjU$ubh information about the current disc that is inserted in the drive. This functionality used to be implemented in the low level drivers, but is now carried out entirely in Uniform CD-ROM Driver.}(hjU$hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhjR$ubh)}(hXmThe history of development of the CD's use as a carrier medium for various digital information has lead to many different disc types. This *ioctl* is useful only in the case that CDs have \emph {only one} type of data on them. While this is often the case, it is also very common for CDs to have some tracks with data, and some tracks with audio. Because this is an existing interface, rather than fixing this interface by changing the assumptions it was made under, thereby breaking all user applications that use this function, the Uniform CD-ROM Driver implements this *ioctl* as follows: If the CD in question has audio tracks on it, and it has absolutely no CD-I, XA, or data tracks on it, it will be reported as *CDS_AUDIO*. If it has both audio and data tracks, it will return *CDS_MIXED*. If there are no audio tracks on the disc, and if the CD in question has any CD-I tracks on it, it will be reported as *CDS_XA_2_2*. Failing that, if the CD in question has any XA tracks on it, it will be reported as *CDS_XA_2_1*. Finally, if the CD in question has any data tracks on it, it will be reported as a data CD (*CDS_DATA_1*).h](hThe history of development of the CD’s use as a carrier medium for various digital information has lead to many different disc types. This }(hj$hhhNhNubjT)}(h*ioctl*h]hioctl}(hj$hhhNhNubah}(h]h ]h"]h$]h&]uh1jShj$ubhX is useful only in the case that CDs have emph {only one} type of data on them. While this is often the case, it is also very common for CDs to have some tracks with data, and some tracks with audio. Because this is an existing interface, rather than fixing this interface by changing the assumptions it was made under, thereby breaking all user applications that use this function, the Uniform CD-ROM Driver implements this }(hj$hhhNhNubjT)}(h*ioctl*h]hioctl}(hj$hhhNhNubah}(h]h ]h"]h$]h&]uh1jShj$ubh as follows: If the CD in question has audio tracks on it, and it has absolutely no CD-I, XA, or data tracks on it, it will be reported as }(hj$hhhNhNubjT)}(h *CDS_AUDIO*h]h CDS_AUDIO}(hj$hhhNhNubah}(h]h ]h"]h$]h&]uh1jShj$ubh7. If it has both audio and data tracks, it will return }(hj$hhhNhNubjT)}(h *CDS_MIXED*h]h CDS_MIXED}(hj$hhhNhNubah}(h]h ]h"]h$]h&]uh1jShj$ubhx. If there are no audio tracks on the disc, and if the CD in question has any CD-I tracks on it, it will be reported as }(hj$hhhNhNubjT)}(h *CDS_XA_2_2*h]h CDS_XA_2_2}(hj$hhhNhNubah}(h]h ]h"]h$]h&]uh1jShj$ubhV. Failing that, if the CD in question has any XA tracks on it, it will be reported as }(hj$hhhNhNubjT)}(h *CDS_XA_2_1*h]h CDS_XA_2_1}(hj$hhhNhNubah}(h]h ]h"]h$]h&]uh1jShj$ubh^. Finally, if the CD in question has any data tracks on it, it will be reported as a data CD (}(hj$hhhNhNubjT)}(h *CDS_DATA_1*h]h CDS_DATA_1}(hj %hhhNhNubah}(h]h ]h"]h$]h&]uh1jShj$ubh).}(hj$hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhjR$ubh)}(hThis *ioctl* can return::h](hThis }(hj%%hhhNhNubjT)}(h*ioctl*h]hioctl}(hj-%hhhNhNubah}(h]h ]h"]h$]h&]uh1jShj%%ubh can return:}(hj%%hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhjR$ubj)}(hXCDS_NO_INFO /* no information available */ CDS_NO_DISC /* no disc is inserted, or tray is opened */ CDS_AUDIO /* Audio disc (2352 audio bytes/frame) */ CDS_DATA_1 /* data disc, mode 1 (2048 user bytes/frame) */ CDS_XA_2_1 /* mixed data (XA), mode 2, form 1 (2048 user bytes) */ CDS_XA_2_2 /* mixed data (XA), mode 2, form 1 (2324 user bytes) */ CDS_MIXED /* mixed audio/data disc */h]hXCDS_NO_INFO /* no information available */ CDS_NO_DISC /* no disc is inserted, or tray is opened */ CDS_AUDIO /* Audio disc (2352 audio bytes/frame) */ CDS_DATA_1 /* data disc, mode 1 (2048 user bytes/frame) */ CDS_XA_2_1 /* mixed data (XA), mode 2, form 1 (2048 user bytes) */ CDS_XA_2_2 /* mixed data (XA), mode 2, form 1 (2324 user bytes) */ CDS_MIXED /* mixed audio/data disc */}hjE%sbah}(h]h ]h"]h$]h&]jjuh1jhhhMhjR$ubh)}(hjFor some information concerning frame layout of the various disc types, see a recent version of `cdrom.h`.h](h`For some information concerning frame layout of the various disc types, see a recent version of }(hjS%hhhNhNubj@)}(h `cdrom.h`h]hcdrom.h}(hj[%hhhNhNubah}(h]h ]h"]h$]h&]uh1j?hjS%ubh.}(hjS%hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhjR$ubeh}(h]h ]h"]h$]h&]uh1jhj7$ubeh}(h]h ]h"]h$]h&]uh1jhhhMhj hhubj)}(hA`CDROM_CHANGER_NSLOTS` Returns the number of slots in a juke-box.h](j)}(h`CDROM_CHANGER_NSLOTS`h]j@)}(hj%h]hCDROM_CHANGER_NSLOTS}(hj%hhhNhNubah}(h]h ]h"]h$]h&]uh1j?hj%ubah}(h]h ]h"]h$]h&]uh1jhhhMhj%ubj)}(hhh]h)}(h*Returns the number of slots in a juke-box.h]h*Returns the number of slots in a juke-box.}(hj%hhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhMhj%ubah}(h]h ]h"]h$]h&]uh1jhj%ubeh}(h]h ]h"]h$]h&]uh1jhhhMhj hhubj)}(h`CDROMRESET` Reset the drive.h](j)}(h `CDROMRESET`h]j@)}(hj%h]h CDROMRESET}(hj%hhhNhNubah}(h]h ]h"]h$]h&]uh1j?hj%ubah}(h]h ]h"]h$]h&]uh1jhhhMhj%ubj)}(hhh]h)}(hReset the drive.h]hReset the drive.}(hj%hhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhMhj%ubah}(h]h ]h"]h$]h&]uh1jhj%ubeh}(h]h ]h"]h$]h&]uh1jhhhMhj hhubj)}(h`CDROM_GET_CAPABILITY` Returns the *capability* flags for the drive. Refer to section cdrom_capabilities_ for more information on these flags.h](j)}(h`CDROM_GET_CAPABILITY`h]j@)}(hj%h]hCDROM_GET_CAPABILITY}(hj%hhhNhNubah}(h]h ]h"]h$]h&]uh1j?hj%ubah}(h]h ]h"]h$]h&]uh1jhhhMhj%ubj)}(hhh]h)}(hwReturns the *capability* flags for the drive. Refer to section cdrom_capabilities_ for more information on these flags.h](h Returns the }(hj &hhhNhNubjT)}(h *capability*h]h capability}(hj&hhhNhNubah}(h]h ]h"]h$]h&]uh1jShj &ubh' flags for the drive. Refer to section }(hj &hhhNhNubh)}(hcdrom_capabilities_h]hcdrom_capabilities}(hj'&hhhNhNubah}(h]h ]h"]h$]h&]namecdrom_capabilitiesjjuh1hhj &jKubh% for more information on these flags.}(hj &hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhj &ubah}(h]h ]h"]h$]h&]uh1jhj%ubeh}(h]h ]h"]h$]h&]uh1jhhhMhj hhubj)}(hd`CDROM_LOCKDOOR` Locks the door of the drive. `arg == 0` unlocks the door, any other value locks it.h](j)}(h`CDROM_LOCKDOOR`h]j@)}(hjS&h]hCDROM_LOCKDOOR}(hjU&hhhNhNubah}(h]h ]h"]h$]h&]uh1j?hjQ&ubah}(h]h ]h"]h$]h&]uh1jhhhMhjM&ubj)}(hhh]h)}(hSLocks the door of the drive. `arg == 0` unlocks the door, any other value locks it.h](hLocks the door of the drive. }(hjk&hhhNhNubj@)}(h `arg == 0`h]harg == 0}(hjs&hhhNhNubah}(h]h ]h"]h$]h&]uh1j?hjk&ubh, unlocks the door, any other value locks it.}(hjk&hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhjh&ubah}(h]h ]h"]h$]h&]uh1jhjM&ubeh}(h]h ]h"]h$]h&]uh1jhhhMhj hhubj)}(hk`CDROM_DEBUG` Turns on debugging info. Only root is allowed to do this. Same semantics as CDROM_LOCKDOOR. h](j)}(h `CDROM_DEBUG`h]j@)}(hj&h]h CDROM_DEBUG}(hj&hhhNhNubah}(h]h ]h"]h$]h&]uh1j?hj&ubah}(h]h ]h"]h$]h&]uh1jhhhMhj&ubj)}(hhh]h)}(h[Turns on debugging info. Only root is allowed to do this. Same semantics as CDROM_LOCKDOOR.h]h[Turns on debugging info. Only root is allowed to do this. Same semantics as CDROM_LOCKDOOR.}(hj&hhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhMhj&ubah}(h]h ]h"]h$]h&]uh1jhj&ubeh}(h]h ]h"]h$]h&]uh1jhhhMhj hhubeh}(h]h ]h"]h$]h&]uh1jhj hhhhhNubeh}(h]new-ioctl-s-in-cdrom-cah ]h"]new ioctl()'s in cdrom.cah$]h&]uh1hhjhhhhhMfubh)}(hhh](h)}(hDevice dependent *ioctl()'s*h](hDevice dependent }(hj&hhhNhNubjT)}(h *ioctl()'s*h]h ioctl()’s}(hj&hhhNhNubah}(h]h ]h"]h$]h&]uh1jShj&ubeh}(h]h ]h"]h$]h&]uh1hhj&hhhhhMubh)}(hFinally, all other *ioctl()'s* are passed to the function *dev_ioctl()*, if implemented. No memory allocation or verification is carried out.h](hFinally, all other }(hj&hhhNhNubjT)}(h *ioctl()'s*h]h ioctl()’s}(hj'hhhNhNubah}(h]h ]h"]h$]h&]uh1jShj&ubh are passed to the function }(hj&hhhNhNubjT)}(h *dev_ioctl()*h]h dev_ioctl()}(hj'hhhNhNubah}(h]h ]h"]h$]h&]uh1jShj&ubhF, if implemented. No memory allocation or verification is carried out.}(hj&hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhj&hhubeh}(h]device-dependent-ioctl-sah ]h"]device dependent ioctl()'sah$]h&]uh1hhjhhhhhMubeh}(h]"description-of-routines-in-cdrom-cah ]h"]"description of routines in cdrom.cah$]h&]uh1hhhhhhhhMubh)}(hhh](h)}(hHow to update your driverh]hHow to update your driver}(hjA'hhhNhNubah}(h]h ]h"]h$]h&]uh1hhj>'hhhhhMubj)}(hhh](j)}(h%Make a backup of your current driver.h]h)}(hjT'h]h%Make a backup of your current driver.}(hjV'hhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhMhjR'ubah}(h]h ]h"]h$]h&]uh1jhjO'hhhhhNubj)}(hvGet hold of the files `cdrom.c` and `cdrom.h`, they should be in the directory tree that came with this documentation.h]h)}(hvGet hold of the files `cdrom.c` and `cdrom.h`, they should be in the directory tree that came with this documentation.h](hGet hold of the files }(hjm'hhhNhNubj@)}(h `cdrom.c`h]hcdrom.c}(hju'hhhNhNubah}(h]h ]h"]h$]h&]uh1j?hjm'ubh and }(hjm'hhhNhNubj@)}(h `cdrom.h`h]hcdrom.h}(hj'hhhNhNubah}(h]h ]h"]h$]h&]uh1j?hjm'ubhI, they should be in the directory tree that came with this documentation.}(hjm'hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhji'ubah}(h]h ]h"]h$]h&]uh1jhjO'hhhhhNubj)}(h Make sure you include `cdrom.h`.h]h)}(hj'h](hMake sure you include }(hj'hhhNhNubj@)}(h `cdrom.h`h]hcdrom.h}(hj'hhhNhNubah}(h]h ]h"]h$]h&]uh1j?hj'ubh.}(hj'hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhj'ubah}(h]h ]h"]h$]h&]uh1jhjO'hhhhhNubj)}(hXChange the 3rd argument of *register_blkdev* from `&_fops` to `&cdrom_fops`.h]h)}(hXChange the 3rd argument of *register_blkdev* from `&_fops` to `&cdrom_fops`.h](hChange the 3rd argument of }(hj'hhhNhNubjT)}(h*register_blkdev*h]hregister_blkdev}(hj'hhhNhNubah}(h]h ]h"]h$]h&]uh1jShj'ubh from }(hj'hhhNhNubj@)}(h`&_fops`h]h&_fops}(hj'hhhNhNubah}(h]h ]h"]h$]h&]uh1j?hj'ubh to }(hj'hhhNhNubj@)}(h `&cdrom_fops`h]h &cdrom_fops}(hj'hhhNhNubah}(h]h ]h"]h$]h&]uh1j?hj'ubh.}(hj'hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhj'ubah}(h]h ]h"]h$]h&]uh1jhjO'hhhhhNubj)}(hJust after that line, add the following to register with the Uniform CD-ROM Driver:: register_cdrom(&_info);* Similarly, add a call to *unregister_cdrom()* at the appropriate place.h](h)}(hTJust after that line, add the following to register with the Uniform CD-ROM Driver::h]hSJust after that line, add the following to register with the Uniform CD-ROM Driver:}(hj (hhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhMhj(ubj)}(h$register_cdrom(&_info);*h]h$register_cdrom(&_info);*}hj.(sbah}(h]h ]h"]h$]h&]jjuh1jhhhMhj(ubh)}(hGSimilarly, add a call to *unregister_cdrom()* at the appropriate place.h](hSimilarly, add a call to }(hj<(hhhNhNubjT)}(h*unregister_cdrom()*h]hunregister_cdrom()}(hjD(hhhNhNubah}(h]h ]h"]h$]h&]uh1jShj<(ubh at the appropriate place.}(hj<(hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhj(ubeh}(h]h ]h"]h$]h&]uh1jhjO'hhhhhNubj)}(hXCopy an example of the device-operations *struct* to your source, e. g., from `cm206.c` *cm206_dops*, and change all entries to names corresponding to your driver, or names you just happen to like. If your driver doesn't support a certain function, make the entry *NULL*. At the entry *capability* you should list all capabilities your driver currently supports. If your driver has a capability that is not listed, please send me a message.h]h)}(hXCopy an example of the device-operations *struct* to your source, e. g., from `cm206.c` *cm206_dops*, and change all entries to names corresponding to your driver, or names you just happen to like. If your driver doesn't support a certain function, make the entry *NULL*. At the entry *capability* you should list all capabilities your driver currently supports. If your driver has a capability that is not listed, please send me a message.h](h)Copy an example of the device-operations }(hjf(hhhNhNubjT)}(h*struct*h]hstruct}(hjn(hhhNhNubah}(h]h ]h"]h$]h&]uh1jShjf(ubh to your source, e. g., from }(hjf(hhhNhNubj@)}(h `cm206.c`h]hcm206.c}(hj(hhhNhNubah}(h]h ]h"]h$]h&]uh1j?hjf(ubh }(hjf(hhhNhNubjT)}(h *cm206_dops*h]h cm206_dops}(hj(hhhNhNubah}(h]h ]h"]h$]h&]uh1jShjf(ubh, and change all entries to names corresponding to your driver, or names you just happen to like. If your driver doesn’t support a certain function, make the entry }(hjf(hhhNhNubjT)}(h*NULL*h]hNULL}(hj(hhhNhNubah}(h]h ]h"]h$]h&]uh1jShjf(ubh. At the entry }(hjf(hhhNhNubjT)}(h *capability*h]h capability}(hj(hhhNhNubah}(h]h ]h"]h$]h&]uh1jShjf(ubh you should list all capabilities your driver currently supports. If your driver has a capability that is not listed, please send me a message.}(hjf(hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhjb(ubah}(h]h ]h"]h$]h&]uh1jhjO'hhhhhNubj)}(hCopy the *cdrom_device_info* declaration from the same example driver, and modify the entries according to your needs. If your driver dynamically determines the capabilities of the hardware, this structure should also be declared dynamically.h]h)}(hCopy the *cdrom_device_info* declaration from the same example driver, and modify the entries according to your needs. If your driver dynamically determines the capabilities of the hardware, this structure should also be declared dynamically.h](h Copy the }(hj(hhhNhNubjT)}(h*cdrom_device_info*h]hcdrom_device_info}(hj(hhhNhNubah}(h]h ]h"]h$]h&]uh1jShj(ubh declaration from the same example driver, and modify the entries according to your needs. If your driver dynamically determines the capabilities of the hardware, this structure should also be declared dynamically.}(hj(hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhj(ubah}(h]h ]h"]h$]h&]uh1jhjO'hhhhhNubj)}(hX Implement all functions in your `_dops` structure, according to prototypes listed in `cdrom.h`, and specifications given in cdrom_api_. Most likely you have already implemented the code in a large part, and you will almost certainly need to adapt the prototype and return values.h]h)}(hX Implement all functions in your `_dops` structure, according to prototypes listed in `cdrom.h`, and specifications given in cdrom_api_. Most likely you have already implemented the code in a large part, and you will almost certainly need to adapt the prototype and return values.h](h Implement all functions in your }(hj)hhhNhNubj@)}(h`_dops`h]h _dops}(hj )hhhNhNubah}(h]h ]h"]h$]h&]uh1j?hj)ubh/ structure, according to prototypes listed in }(hj)hhhNhNubj@)}(h `cdrom.h`h]hcdrom.h}(hj)hhhNhNubah}(h]h ]h"]h$]h&]uh1j?hj)ubh, and specifications given in }(hj)hhhNhNubh)}(h cdrom_api_h]h cdrom_api}(hj.)hhhNhNubah}(h]h ]h"]h$]h&]name cdrom_apijjuh1hhj)jKubh. Most likely you have already implemented the code in a large part, and you will almost certainly need to adapt the prototype and return values.}(hj)hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhj(ubah}(h]h ]h"]h$]h&]uh1jhjO'hhhhhNubj)}(hRename your `_ioctl()` function to *audio_ioctl* and change the prototype a little. Remove entries listed in the first part in cdrom_ioctl_, if your code was OK, these are just calls to the routines you adapted in the previous step.h]h)}(hRename your `_ioctl()` function to *audio_ioctl* and change the prototype a little. Remove entries listed in the first part in cdrom_ioctl_, if your code was OK, these are just calls to the routines you adapted in the previous step.h](h Rename your }(hjR)hhhNhNubj@)}(h`_ioctl()`h]h_ioctl()}(hjZ)hhhNhNubah}(h]h ]h"]h$]h&]uh1j?hjR)ubh function to }(hjR)hhhNhNubjT)}(h *audio_ioctl*h]h audio_ioctl}(hjl)hhhNhNubah}(h]h ]h"]h$]h&]uh1jShjR)ubhO and change the prototype a little. Remove entries listed in the first part in }(hjR)hhhNhNubh)}(h cdrom_ioctl_h]h cdrom_ioctl}(hj~)hhhNhNubah}(h]h ]h"]h$]h&]name cdrom_ioctljj^uh1hhjR)jKubh], if your code was OK, these are just calls to the routines you adapted in the previous step.}(hjR)hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhjN)ubah}(h]h ]h"]h$]h&]uh1jhjO'hhhhhNubj)}(hXrYou may remove all remaining memory checking code in the *audio_ioctl()* function that deals with audio commands (these are listed in the second part of cdrom_ioctl_. There is no need for memory allocation either, so most *case*s in the *switch* statement look similar to:: case CDROMREADTOCENTRY: get_toc_entry\bigl((struct cdrom_tocentry *) arg); h](h)}(hXYou may remove all remaining memory checking code in the *audio_ioctl()* function that deals with audio commands (these are listed in the second part of cdrom_ioctl_. There is no need for memory allocation either, so most *case*s in the *switch* statement look similar to::h](h9You may remove all remaining memory checking code in the }(hj)hhhNhNubjT)}(h*audio_ioctl()*h]h audio_ioctl()}(hj)hhhNhNubah}(h]h ]h"]h$]h&]uh1jShj)ubhQ function that deals with audio commands (these are listed in the second part of }(hj)hhhNhNubh)}(h cdrom_ioctl_h]h cdrom_ioctl}(hj)hhhNhNubah}(h]h ]h"]h$]h&]name cdrom_ioctljj^uh1hhj)jKubh9. There is no need for memory allocation either, so most }(hj)hhhNhNubjT)}(h*case*s in the *switch*h]hcase*s in the *switch}(hj)hhhNhNubah}(h]h ]h"]h$]h&]uh1jShj)ubh statement look similar to:}(hj)hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhj)ubj)}(hRcase CDROMREADTOCENTRY: get_toc_entry\bigl((struct cdrom_tocentry *) arg);h]hRcase CDROMREADTOCENTRY: get_toc_entry\bigl((struct cdrom_tocentry *) arg);}hj)sbah}(h]h ]h"]h$]h&]jjuh1jhhhMhj)ubeh}(h]h ]h"]h$]h&]uh1jhjO'hhhhhNubj)}(hAll remaining *ioctl* cases must be moved to a separate function, *_ioctl*, the device-dependent *ioctl()'s*. Note that memory checking and allocation must be kept in this code!h]h)}(hAll remaining *ioctl* cases must be moved to a separate function, *_ioctl*, the device-dependent *ioctl()'s*. Note that memory checking and allocation must be kept in this code!h](hAll remaining }(hj*hhhNhNubjT)}(h*ioctl*h]hioctl}(hj*hhhNhNubah}(h]h ]h"]h$]h&]uh1jShj*ubh- cases must be moved to a separate function, }(hj*hhhNhNubjT)}(h*_ioctl*h]h_ioctl}(hj*hhhNhNubah}(h]h ]h"]h$]h&]uh1jShj*ubh, the device-dependent }(hj*hhhNhNubjT)}(h *ioctl()'s*h]h ioctl()’s}(hj,*hhhNhNubah}(h]h ]h"]h$]h&]uh1jShj*ubhE. Note that memory checking and allocation must be kept in this code!}(hj*hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhj)ubah}(h]h ]h"]h$]h&]uh1jhjO'hhhhhNubj)}(hChange the prototypes of *_open()* and *_release()*, and remove any strategic code (i. e., tray movement, door locking, etc.).h]h)}(hChange the prototypes of *_open()* and *_release()*, and remove any strategic code (i. e., tray movement, door locking, etc.).h](hChange the prototypes of }(hjN*hhhNhNubjT)}(h*_open()*h]h_open()}(hjV*hhhNhNubah}(h]h ]h"]h$]h&]uh1jShjN*ubh and }(hjN*hhhNhNubjT)}(h*_release()*h]h_release()}(hjh*hhhNhNubah}(h]h ]h"]h$]h&]uh1jShjN*ubhK, and remove any strategic code (i. e., tray movement, door locking, etc.).}(hjN*hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhjJ*ubah}(h]h ]h"]h$]h&]uh1jhjO'hhhhhNubj)}(hTry to recompile the drivers. We advise you to use modules, both for `cdrom.o` and your driver, as debugging is much easier this way. h]h)}(hTry to recompile the drivers. We advise you to use modules, both for `cdrom.o` and your driver, as debugging is much easier this way.h](hETry to recompile the drivers. We advise you to use modules, both for }(hj*hhhNhNubj@)}(h `cdrom.o`h]hcdrom.o}(hj*hhhNhNubah}(h]h ]h"]h$]h&]uh1j?hj*ubh7 and your driver, as debugging is much easier this way.}(hj*hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhj*ubah}(h]h ]h"]h$]h&]uh1jhjO'hhhhhNubeh}(h]h ]h"]h$]h&]j5j6uh1jhhhMhj>'hhubeh}(h]how-to-update-your-driverah ]h"]how to update your driverah$]h&]uh1hhhhhhhhMubh)}(hhh](h)}(hThanksh]hThanks}(hj*hhhNhNubah}(h]h ]h"]h$]h&]uh1hhj*hhhhhM ubh)}(hXThanks to all the people involved. First, Erik Andersen, who has taken over the torch in maintaining `cdrom.c` and integrating much CD-ROM-related code in the 2.1-kernel. Thanks to Scott Snyder and Gerd Knorr, who were the first to implement this interface for SCSI and IDE-CD drivers and added many ideas for extension of the data structures relative to kernel~2.0. Further thanks to Heiko Eißfeldt, Thomas Quinot, Jon Tombs, Ken Pizzini, Eberhard Mönkeberg and Andrew Kroll, the Linux CD-ROM device driver developers who were kind enough to give suggestions and criticisms during the writing. Finally of course, I want to thank Linus Torvalds for making this possible in the first place.h](heThanks to all the people involved. First, Erik Andersen, who has taken over the torch in maintaining }(hj*hhhNhNubj@)}(h `cdrom.c`h]hcdrom.c}(hj*hhhNhNubah}(h]h ]h"]h$]h&]uh1j?hj*ubhXE and integrating much CD-ROM-related code in the 2.1-kernel. Thanks to Scott Snyder and Gerd Knorr, who were the first to implement this interface for SCSI and IDE-CD drivers and added many ideas for extension of the data structures relative to kernel~2.0. Further thanks to Heiko Eißfeldt, Thomas Quinot, Jon Tombs, Ken Pizzini, Eberhard Mönkeberg and Andrew Kroll, the Linux CD-ROM device driver developers who were kind enough to give suggestions and criticisms during the writing. Finally of course, I want to thank Linus Torvalds for making this possible in the first place.}(hj*hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhj*hhubeh}(h]thanksah ]h"]thanksah$]h&]uh1hhhhhhhhM ubeh}(h]a-linux-cd-rom-standardah ]h"]a linux cd-rom standardah$]h&]uh1hhhhhhhhKubeh}(h]h ]h"]h$]h&]sourcehuh1hcurrent_sourceN current_lineNsettingsdocutils.frontendValues)}(hN generatorN datestampN source_linkN source_urlN toc_backlinksentryfootnote_backlinksK sectnum_xformKstrip_commentsNstrip_elements_with_classesN strip_classesN report_levelK halt_levelKexit_status_levelKdebugNwarning_streamN tracebackinput_encoding utf-8-siginput_encoding_error_handlerstrictoutput_encodingutf-8output_encoding_error_handlerj"+error_encodingutf-8error_encoding_error_handlerbackslashreplace language_codeenrecord_dependenciesNconfigN id_prefixhauto_id_prefixid dump_settingsNdump_internalsNdump_transformsNdump_pseudo_xmlNexpose_internalsNstrict_visitorN_disable_configN_sourceh _destinationN _config_files]7/var/lib/git/docbuild/linux/Documentation/docutils.confafile_insertion_enabled raw_enabledKline_length_limitM'pep_referencesN pep_base_urlhttps://peps.python.org/pep_file_url_templatepep-%04drfc_referencesN rfc_base_url&https://datatracker.ietf.org/doc/html/ tab_widthKtrim_footnote_reference_spacesyntax_highlightlong smart_quotessmartquotes_locales]character_level_inline_markupdoctitle_xform docinfo_xformKsectsubtitle_xform image_loadinglinkembed_stylesheetcloak_email_addressessection_self_linkenvNubreporterNindirect_targets]substitution_defs}substitution_names}refnames}(f1]jaf2]jaf3]jUa cdrom_api](jLjj.)ecdrom_drive_status]j#acdrom_capabilities]j'&a cdrom_ioctl](j~)j)eurefids}(j]jaj ]j aj]jaj^]jTaj]jaj]jajd]jUaunameids}(j*j*jjjWjjjjjj j jjj!jj jjj jjj4j1jjdjjj;'j8'jkj^jsjpj j j&j&j3'j0'j*j*j*j*u nametypes}(j*jjWjjj jj!j jjj4jjj;'jkjsj j&j3'j*j*uh}(j*hjjjjjj2jjjjj j jjjjejjjjj j&jjj1j<j_jUjdjojj7j8'jj^j_jpjj jvj&j j0'j&j*j>'j*j*u footnote_refs}(jb+]jajd+]jajf+]jUau citation_refs} autofootnotes](j2jejoeautofootnote_refs](jjjUesymbol_footnotes]symbol_footnote_refs] footnotes] citations]autofootnote_startKsymbol_footnote_startK id_counter collectionsCounter}j0+KsRparse_messages]transform_messages] transformerN include_log] decorationNhhub.