sphinx.addnodesdocument)}( rawsource children](translations
LanguagesNode)}(hhh](h pending_xref)}(hhh]docutils.nodesTextChinese (Simplified)}parenthsba
attributes}(ids]classes]names]dupnames]backrefs] refdomainstdreftypedoc reftarget /translations/zh_CN/hid/hidintromodnameN classnameNrefexplicitutagnamehhhubh)}(hhh]hChinese (Traditional)}hh2sbah}(h]h ]h"]h$]h&] refdomainh)reftypeh+ reftarget /translations/zh_TW/hid/hidintromodnameN classnameNrefexplicituh1hhhubh)}(hhh]hItalian}hhFsbah}(h]h ]h"]h$]h&] refdomainh)reftypeh+ reftarget /translations/it_IT/hid/hidintromodnameN classnameNrefexplicituh1hhhubh)}(hhh]hJapanese}hhZsbah}(h]h ]h"]h$]h&] refdomainh)reftypeh+ reftarget /translations/ja_JP/hid/hidintromodnameN classnameNrefexplicituh1hhhubh)}(hhh]hKorean}hhnsbah}(h]h ]h"]h$]h&] refdomainh)reftypeh+ reftarget /translations/ko_KR/hid/hidintromodnameN classnameNrefexplicituh1hhhubh)}(hhh]hSpanish}hhsbah}(h]h ]h"]h$]h&] refdomainh)reftypeh+ reftarget /translations/sp_SP/hid/hidintromodnameN classnameNrefexplicituh1hhhubeh}(h]h ]h"]h$]h&]current_languageEnglishuh1h
hh _documenthsourceNlineNubhcomment)}(h SPDX-License-Identifier: GPL-2.0h]h SPDX-License-Identifier: GPL-2.0}hhsbah}(h]h ]h"]h$]h&] xml:spacepreserveuh1hhhhhh:/var/lib/git/docbuild/linux/Documentation/hid/hidintro.rsthKubhsection)}(hhh](htitle)}(h&Introduction to HID report descriptorsh]h&Introduction to HID report descriptors}(hhhhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhhhhhKubh paragraph)}(hThis chapter is meant to give a broad overview of what HID report
descriptors are, and of how a casual (non-kernel) programmer can deal
with HID devices that are not working well with Linux.h]hThis chapter is meant to give a broad overview of what HID report
descriptors are, and of how a casual (non-kernel) programmer can deal
with HID devices that are not working well with Linux.}(hhhhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhKhhhhubhtopic)}(hhh]hbullet_list)}(hhh](h list_item)}(hhh]h)}(hhh]h reference)}(hhh]hIntroduction}(hhhhhNhNubah}(h]id4ah ]h"]h$]h&]refidintroductionuh1hhhubah}(h]h ]h"]h$]h&]uh1hhhubah}(h]h ]h"]h$]h&]uh1hhhubh)}(hhh](h)}(hhh]h)}(hhh]hParsing HID report descriptors}(hj hhhNhNubah}(h]id5ah ]h"]h$]h&]refidparsing-hid-report-descriptorsuh1hhj ubah}(h]h ]h"]h$]h&]uh1hhj ubh)}(hhh]h)}(hhh]h)}(hhh]h)}(hhh]h!Output, Input and Feature Reports}(hj. hhhNhNubah}(h]id6ah ]h"]h$]h&]refid output-input-and-feature-reportsuh1hhj+ ubah}(h]h ]h"]h$]h&]uh1hhj( ubah}(h]h ]h"]h$]h&]uh1hhj% ubah}(h]h ]h"]h$]h&]uh1hhj ubeh}(h]h ]h"]h$]h&]uh1hhhubh)}(hhh]h)}(hhh]h)}(hhh]h(Collections, Report IDs and Evdev events}(hj\ hhhNhNubah}(h]id7ah ]h"]h$]h&]refid'collections-report-ids-and-evdev-eventsuh1hhjY ubah}(h]h ]h"]h$]h&]uh1hhjV ubah}(h]h ]h"]h$]h&]uh1hhhubh)}(hhh]h)}(hhh]h)}(hhh]hEvents}(hj~ hhhNhNubah}(h]id8ah ]h"]h$]h&]refideventsuh1hhj{ ubah}(h]h ]h"]h$]h&]uh1hhjx ubah}(h]h ]h"]h$]h&]uh1hhhubh)}(hhh](h)}(hhh]h)}(hhh]hWhen something does not work}(hj hhhNhNubah}(h]id9ah ]h"]h$]h&]refidwhen-something-does-not-workuh1hhj ubah}(h]h ]h"]h$]h&]uh1hhj ubh)}(hhh](h)}(hhh]h)}(hhh]h)}(hhh]hQuirks}(hj hhhNhNubah}(h]id10ah ]h"]h$]h&]refidquirksuh1hhj ubah}(h]h ]h"]h$]h&]uh1hhj ubah}(h]h ]h"]h$]h&]uh1hhj ubh)}(hhh]h)}(hhh]h)}(hhh]hFixing HID report descriptors}(hj hhhNhNubah}(h]id11ah ]h"]h$]h&]refidfixing-hid-report-descriptorsuh1hhj ubah}(h]h ]h"]h$]h&]uh1hhj ubah}(h]h ]h"]h$]h&]uh1hhj ubh)}(hhh]h)}(hhh]h)}(hhh]h)Modifying the transmitted data on the fly}(hj hhhNhNubah}(h]id12ah ]h"]h$]h&]refid)modifying-the-transmitted-data-on-the-flyuh1hhj ubah}(h]h ]h"]h$]h&]uh1hhj ubah}(h]h ]h"]h$]h&]uh1hhj ubh)}(hhh]h)}(hhh]h)}(hhh]hWriting a specialized driver}(hj% hhhNhNubah}(h]id13ah ]h"]h$]h&]refidwriting-a-specialized-driveruh1hhj" ubah}(h]h ]h"]h$]h&]uh1hhj ubah}(h]h ]h"]h$]h&]uh1hhj ubeh}(h]h ]h"]h$]h&]uh1hhj ubeh}(h]h ]h"]h$]h&]uh1hhhubeh}(h]h ]h"]h$]h&]uh1hhhhhhNhNubah}(h]contentsah ](contentslocaleh"]contentsah$]h&]uh1hhhhK
hhhhubhcompound)}(hhh]h toctree)}(hhh]h}(h]h ]h"]h$]h&]hhid/hidintroentries]Nhid/hidreport-parsingaincludefiles]jp amaxdepthKcaptionNglobhidden
includehiddennumberedK
titlesonly
rawentries]uh1jb hhhKhj_ ubah}(h]h ]toctree-wrapperah"]h$]h&]uh1j] hhhhhhhNubh)}(hhh](h)}(hIntroductionh]hIntroduction}(hj hhhNhNubah}(h]h ]h"]h$]h&]refidhuh1hhj hhhhhKubh)}(hHID stands for Human Interface Device, and can be whatever device you
are using to interact with a computer, be it a mouse, a touchpad, a
tablet, a microphone.h]hHID stands for Human Interface Device, and can be whatever device you
are using to interact with a computer, be it a mouse, a touchpad, a
tablet, a microphone.}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhKhj hhubh)}(hXk Many HID devices work out the box, even if their hardware is different.
For example, mice can have any number of buttons; they may have a
wheel; movement sensitivity differs between different models, and so
on. Nonetheless, most of the time everything just works, without the
need to have specialized code in the kernel for every mouse model
developed since 1970.h]hXk Many HID devices work out the box, even if their hardware is different.
For example, mice can have any number of buttons; they may have a
wheel; movement sensitivity differs between different models, and so
on. Nonetheless, most of the time everything just works, without the
need to have specialized code in the kernel for every mouse model
developed since 1970.}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhKhj hhubh)}(hX This is because modern HID devices do advertise their capabilities
through the *HID report descriptor*, a fixed set of bytes describing
exactly what *HID reports* may be sent between the device and the host
and the meaning of each individual bit in those reports. For example,
a HID Report Descriptor may specify that "in a report with ID 3 the
bits from 8 to 15 is the delta x coordinate of a mouse".h](hOThis is because modern HID devices do advertise their capabilities
through the }(hj hhhNhNubhemphasis)}(h*HID report descriptor*h]hHID report descriptor}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1j hj ubh/, a fixed set of bytes describing
exactly what }(hj hhhNhNubj )}(h
*HID reports*h]hHID reports}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1j hj ubh may be sent between the device and the host
and the meaning of each individual bit in those reports. For example,
a HID Report Descriptor may specify that “in a report with ID 3 the
bits from 8 to 15 is the delta x coordinate of a mouse”.}(hj hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhK#hj hhubh)}(hXU The HID report itself then merely carries the actual data values
without any extra meta information. Note that HID reports may be sent
from the device ("Input Reports", i.e. input events), to the device
("Output Reports" to e.g. change LEDs) or used for device configuration
("Feature reports"). A device may support one or more HID reports.h]hXa The HID report itself then merely carries the actual data values
without any extra meta information. Note that HID reports may be sent
from the device (“Input Reports”, i.e. input events), to the device
(“Output Reports” to e.g. change LEDs) or used for device configuration
(“Feature reports”). A device may support one or more HID reports.}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhK*hj hhubh)}(hX The HID subsystem is in charge of parsing the HID report descriptors,
and converts HID events into normal input device interfaces (see
Documentation/hid/hid-transport.rst). Devices may misbehave because the
HID report descriptor provided by the device is wrong, or because it
needs to be dealt with in a special way, or because some special
device or interaction mode is not handled by the default code.h]hX The HID subsystem is in charge of parsing the HID report descriptors,
and converts HID events into normal input device interfaces (see
Documentation/hid/hid-transport.rst). Devices may misbehave because the
HID report descriptor provided by the device is wrong, or because it
needs to be dealt with in a special way, or because some special
device or interaction mode is not handled by the default code.}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhK0hj hhubh)}(hThe format of HID report descriptors is described by two documents,
available from the `USB Implementers Forum `_
`HID web page `_ address:h](hWThe format of HID report descriptors is described by two documents,
available from the }(hj hhhNhNubh)}(h0`USB Implementers Forum `_h]hUSB Implementers Forum}(hj
hhhNhNubah}(h]h ]h"]h$]h&]nameUSB Implementers Forumrefurihttps://www.usb.org/uh1hhj ubhtarget)}(h h]h}(h]usb-implementers-forumah ]h"]usb implementers forumah$]h&]refurij uh1j
referencedKhj ubh
}(hj hhhNhNubh)}(h)`HID web page `_h]hHID web page}(hj0 hhhNhNubah}(h]h ]h"]h$]h&]nameHID web pagej https://www.usb.org/hiduh1hhj ubj )}(h h]h}(h]hid-web-pageah ]h"]hid web pageah$]h&]refurij@ uh1j j+ Khj ubh address:}(hj hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhK7hj hhubhblock_quote)}(h* the `HID USB Device Class Definition
`_ (HID Spec from now on)
* the `HID Usage Tables `_ (HUT from now on)
h]h)}(hhh](h)}(hthe `HID USB Device Class Definition
`_ (HID Spec from now on)h]h)}(hthe `HID USB Device Class Definition
`_ (HID Spec from now on)h](hthe }(hje hhhNhNubh)}(hi`HID USB Device Class Definition
`_h]hHID USB Device Class Definition}(hjm hhhNhNubah}(h]h ]h"]h$]h&]nameHID USB Device Class Definitionj Dhttps://www.usb.org/document-library/device-class-definition-hid-111uh1hhje ubj )}(hG
h]h}(h]hid-usb-device-class-definitionah ]h"]hid usb device class definitionah$]h&]refurij} uh1j j+ Khje ubh (HID Spec from now on)}(hje hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhK;hja ubah}(h]h ]h"]h$]h&]uh1hhj^ ubh)}(hathe `HID Usage Tables `_ (HUT from now on)
h]h)}(h`the `HID Usage Tables `_ (HUT from now on)h](hthe }(hj hhhNhNubh)}(hJ`HID Usage Tables `_h]hHID Usage Tables}(hj hhhNhNubah}(h]h ]h"]h$]h&]nameHID Usage Tablesj 4https://usb.org/document-library/hid-usage-tables-14uh1hhj ubj )}(h7 h]h}(h]hid-usage-tablesah ]h"]hid usage tablesah$]h&]refurij uh1j j+ Khj ubh (HUT from now on)}(hj hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhK=hj ubah}(h]h ]h"]h$]h&]uh1hhj^ ubeh}(h]h ]h"]h$]h&]bullet*uh1hhhhK;hjZ ubah}(h]h ]h"]h$]h&]uh1jX hhhK;hj hhubh)}(hThe HID subsystem can deal with different transport drivers
(USB, I2C, Bluetooth, etc.). See Documentation/hid/hid-transport.rst.h]hThe HID subsystem can deal with different transport drivers
(USB, I2C, Bluetooth, etc.). See Documentation/hid/hid-transport.rst.}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhK?hj hhubeh}(h]hah ]h"]introductionah$]h&]uh1hhhhhhhhKubh)}(hhh](h)}(hParsing HID report descriptorsh]hParsing HID report descriptors}(hj hhhNhNubah}(h]h ]h"]h$]h&]j j uh1hhj hhhhhKCubh)}(hThe current list of HID devices can be found at ``/sys/bus/hid/devices/``.
For each device, say ``/sys/bus/hid/devices/0003\:093A\:2510.0002/``,
one can read the corresponding report descriptor::h](h0The current list of HID devices can be found at }(hj hhhNhNubhliteral)}(h``/sys/bus/hid/devices/``h]h/sys/bus/hid/devices/}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1j hj ubh.
For each device, say }(hj hhhNhNubj )}(h/``/sys/bus/hid/devices/0003\:093A\:2510.0002/``h]h+/sys/bus/hid/devices/0003\:093A\:2510.0002/}(hj% hhhNhNubah}(h]h ]h"]h$]h&]uh1j hj ubh3,
one can read the corresponding report descriptor:}(hj hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhKEhj hhubh
literal_block)}(hX $ hexdump -C /sys/bus/hid/devices/0003\:093A\:2510.0002/report_descriptor
00000000 05 01 09 02 a1 01 09 01 a1 00 05 09 19 01 29 03 |..............).|
00000010 15 00 25 01 75 01 95 03 81 02 75 05 95 01 81 01 |..%.u.....u.....|
00000020 05 01 09 30 09 31 09 38 15 81 25 7f 75 08 95 03 |...0.1.8..%.u...|
00000030 81 06 c0 c0 |....|
00000034h]hX $ hexdump -C /sys/bus/hid/devices/0003\:093A\:2510.0002/report_descriptor
00000000 05 01 09 02 a1 01 09 01 a1 00 05 09 19 01 29 03 |..............).|
00000010 15 00 25 01 75 01 95 03 81 02 75 05 95 01 81 01 |..%.u.....u.....|
00000020 05 01 09 30 09 31 09 38 15 81 25 7f 75 08 95 03 |...0.1.8..%.u...|
00000030 81 06 c0 c0 |....|
00000034}hj? sbah}(h]h ]h"]h$]h&]hhuh1j= hhhKIhj hhubh)}(hhOptional: the HID report descriptor can be read also by
directly accessing the hidraw driver [#hidraw]_.h](h]Optional: the HID report descriptor can be read also by
directly accessing the hidraw driver }(hjM hhhNhNubhfootnote_reference)}(h
[#hidraw]_h]h1}(hjW hhhNhNubah}(h]id1ah ]h"]h$]h&]autoKj hidrawdocnamejm uh1jU hjM resolvedKubh.}(hjM hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhKPhj hhubh)}(hX The basic structure of HID report descriptors is defined in the HID
spec, while HUT "defines constants that can be interpreted by an
application to identify the purpose and meaning of a data field in a
HID report". Each entry is defined by at least two bytes, where the
first one defines what type of value is following and is described in
the HID spec, while the second one carries the actual value and is
described in the HUT.h]hX The basic structure of HID report descriptors is defined in the HID
spec, while HUT “defines constants that can be interpreted by an
application to identify the purpose and meaning of a data field in a
HID report”. Each entry is defined by at least two bytes, where the
first one defines what type of value is following and is described in
the HID spec, while the second one carries the actual value and is
described in the HUT.}(hjt hhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhKShj hhubh)}(hXHID report descriptors can, in principle, be painstakingly parsed by
hand, byte by byte.h]hXHID report descriptors can, in principle, be painstakingly parsed by
hand, byte by byte.}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhK[hj hhubh)}(hA short introduction on how to do this is sketched in
Documentation/hid/hidreport-parsing.rst; you only need to understand it
if you need to patch HID report descriptors.h]hA short introduction on how to do this is sketched in
Documentation/hid/hidreport-parsing.rst; you only need to understand it
if you need to patch HID report descriptors.}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhK^hj hhubh)}(hIn practice you should not parse HID report descriptors by hand; rather,
you should use an existing parser. Among all the available onesh]hIn practice you should not parse HID report descriptors by hand; rather,
you should use an existing parser. Among all the available ones}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhKbhj hhubjY )}(hX@ * the online `USB Descriptor and Request Parser
`_;
* `hidrdd `_,
that provides very detailed and somewhat verbose descriptions
(verbosity can be useful if you are not familiar with HID report
descriptors);
* `hid-tools `_,
a complete utility set that allows, among other things,
to record and replay the raw HID reports and to debug
and replay HID devices.
It is being actively developed by the Linux HID subsystem maintainers.
h]h)}(hhh](h)}(h]the online `USB Descriptor and Request Parser
`_;h]h)}(h]the online `USB Descriptor and Request Parser
`_;h](hthe online }(hj hhhNhNubh)}(hQ`USB Descriptor and Request Parser
`_h]h!USB Descriptor and Request Parser}(hj hhhNhNubah}(h]h ]h"]h$]h&]name!USB Descriptor and Request Parserj *http://eleccelerator.com/usbdescreqparser/uh1hhj ubj )}(h-
h]h}(h]!usb-descriptor-and-request-parserah ]h"]!usb descriptor and request parserah$]h&]refurij uh1j j+ Khj ubh;}(hj hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhKehj ubah}(h]h ]h"]h$]h&]uh1hhj ubh)}(h`hidrdd `_,
that provides very detailed and somewhat verbose descriptions
(verbosity can be useful if you are not familiar with HID report
descriptors);h]h)}(h`hidrdd `_,
that provides very detailed and somewhat verbose descriptions
(verbosity can be useful if you are not familiar with HID report
descriptors);h](h)}(h.`hidrdd `_h]hhidrdd}(hj hhhNhNubah}(h]h ]h"]h$]h&]namehidrddj "https://github.com/abend0c1/hidrdduh1hhj ubj )}(h% h]h}(h]hidrddah ]h"]hidrddah$]h&]refurij uh1j j+ Khj ubh,
that provides very detailed and somewhat verbose descriptions
(verbosity can be useful if you are not familiar with HID report
descriptors);}(hj hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhKghj ubah}(h]h ]h"]h$]h&]uh1hhj ubh)}(hX `hid-tools `_,
a complete utility set that allows, among other things,
to record and replay the raw HID reports and to debug
and replay HID devices.
It is being actively developed by the Linux HID subsystem maintainers.
h]h)}(hX `hid-tools `_,
a complete utility set that allows, among other things,
to record and replay the raw HID reports and to debug
and replay HID devices.
It is being actively developed by the Linux HID subsystem maintainers.h](h)}(h@`hid-tools `_h]h hid-tools}(hj+ hhhNhNubah}(h]h ]h"]h$]h&]name hid-toolsj 1https://gitlab.freedesktop.org/libevdev/hid-toolsuh1hhj' ubj )}(h4 h]h}(h] hid-toolsah ]h"] hid-toolsah$]h&]refurij; uh1j j+ Khj' ubh,
a complete utility set that allows, among other things,
to record and replay the raw HID reports and to debug
and replay HID devices.
It is being actively developed by the Linux HID subsystem maintainers.}(hj' hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhKkhj# ubah}(h]h ]h"]h$]h&]uh1hhj ubeh}(h]h ]h"]h$]h&]j j uh1hhhhKehj ubah}(h]h ]h"]h$]h&]uh1jX hhhKehj hhubh)}(hParsing the mouse HID report descriptor with `hid-tools
`_ leads to
(explanations interposed)::h](h-Parsing the mouse HID report descriptor with }(hje hhhNhNubh)}(h@`hid-tools
`_h]h hid-tools}(hjm hhhNhNubah}(h]h ]h"]h$]h&]name hid-toolsj 1https://gitlab.freedesktop.org/libevdev/hid-toolsuh1hhje ubj )}(h4
h]h}(h]id2ah ]h"]h$] hid-toolsah&]refurij} uh1j j+ Khje ubh$ leads to
(explanations interposed):}(hje hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhKqhj hhubj> )}(hX $ ./hid-decode /sys/bus/hid/devices/0003\:093A\:2510.0002/report_descriptor
# device 0:0
# 0x05, 0x01, // Usage Page (Generic Desktop) 0
# 0x09, 0x02, // Usage (Mouse) 2
# 0xa1, 0x01, // Collection (Application) 4
# 0x09, 0x01, // Usage (Pointer) 6
# 0xa1, 0x00, // Collection (Physical) 8
# 0x05, 0x09, // Usage Page (Button) 10h]hX $ ./hid-decode /sys/bus/hid/devices/0003\:093A\:2510.0002/report_descriptor
# device 0:0
# 0x05, 0x01, // Usage Page (Generic Desktop) 0
# 0x09, 0x02, // Usage (Mouse) 2
# 0xa1, 0x01, // Collection (Application) 4
# 0x09, 0x01, // Usage (Pointer) 6
# 0xa1, 0x00, // Collection (Physical) 8
# 0x05, 0x09, // Usage Page (Button) 10}hj sbah}(h]h ]h"]h$]h&]hhuh1j= hhhKuhj hhubh)}(hwhat follows is a button ::h]hwhat follows is a button}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhK~hj hhubj> )}(h# 0x19, 0x01, // Usage Minimum (1) 12
# 0x29, 0x03, // Usage Maximum (3) 14h]h# 0x19, 0x01, // Usage Minimum (1) 12
# 0x29, 0x03, // Usage Maximum (3) 14}hj sbah}(h]h ]h"]h$]h&]hhuh1j= hhhKhj hhubh)}(hBfirst button is button number 1, last button is button number 3 ::h]h?first button is button number 1, last button is button number 3}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhKhj hhubj> )}(h# 0x15, 0x00, // Logical Minimum (0) 16
# 0x25, 0x01, // Logical Maximum (1) 18h]h# 0x15, 0x00, // Logical Minimum (0) 16
# 0x25, 0x01, // Logical Maximum (1) 18}hj sbah}(h]h ]h"]h$]h&]hhuh1j= hhhKhj hhubh)}(hVeach button can send values from 0 up to including 1
(i.e. they are binary buttons) ::h]hSeach button can send values from 0 up to including 1
(i.e. they are binary buttons)}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhKhj hhubj> )}(hI# 0x75, 0x01, // Report Size (1) 20h]hI# 0x75, 0x01, // Report Size (1) 20}hj sbah}(h]h ]h"]h$]h&]hhuh1j= hhhKhj hhubh)}(h)each button is sent as exactly one bit ::h]h&each button is sent as exactly one bit}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhKhj hhubj> )}(hI# 0x95, 0x03, // Report Count (3) 22h]hI# 0x95, 0x03, // Report Count (3) 22}hj sbah}(h]h ]h"]h$]h&]hhuh1j= hhhKhj hhubh)}(hAand there are three of those bits (matching the three buttons) ::h]h>and there are three of those bits (matching the three buttons)}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhKhj hhubj> )}(hI# 0x81, 0x02, // Input (Data,Var,Abs) 24h]hI# 0x81, 0x02, // Input (Data,Var,Abs) 24}hj! sbah}(h]h ]h"]h$]h&]hhuh1j= hhhKhj hhubh)}(hit's actual Data (not constant padding), they represent
a single variable (Var) and their values are Absolute (not relative);
See HID spec Sec. 6.2.2.5 "Input, Output, and Feature Items" ::h]hit’s actual Data (not constant padding), they represent
a single variable (Var) and their values are Absolute (not relative);
See HID spec Sec. 6.2.2.5 “Input, Output, and Feature Items”}(hj/ hhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhKhj hhubj> )}(hI# 0x75, 0x05, // Report Size (5) 26h]hI# 0x75, 0x05, // Report Size (5) 26}hj= sbah}(h]h ]h"]h$]h&]hhuh1j= hhhKhj hhubh)}(h7five additional padding bits, needed to reach a byte ::h]h4five additional padding bits, needed to reach a byte}(hjK hhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhKhj hhubj> )}(hI# 0x95, 0x01, // Report Count (1) 28h]hI# 0x95, 0x01, // Report Count (1) 28}hjY sbah}(h]h ]h"]h$]h&]hhuh1j= hhhKhj hhubh)}(h)those five bits are repeated only once ::h]h&those five bits are repeated only once}(hjg hhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhKhj hhubj> )}(hI# 0x81, 0x01, // Input (Cnst,Arr,Abs) 30h]hI# 0x81, 0x01, // Input (Cnst,Arr,Abs) 30}hju sbah}(h]h ]h"]h$]h&]hhuh1j= hhhKhj hhubh)}(h