€•~/      Œsphinx.addnodes”Œdocument”“”)”}”(Œ	rawsource”Œ ”Œchildren”]”(Œtranslations”ŒLanguagesNode”“”)”}”(hhh]”(h Œpending_xref”“”)”}”(hhh]”Œdocutils.nodes”ŒText”“”ŒChinese (Simplified)”…””}”Œparent”hsbaŒ
attributes”}”(Œids”]”Œclasses”]”Œnames”]”Œdupnames”]”Œbackrefs”]”Œ	refdomain”Œstd”Œreftype”Œdoc”Œ	reftarget”Œ6/translations/zh_CN/driver-api/firmware/firmware_cache”Œmodname”NŒ	classname”NŒrefexplicit”ˆuŒtagname”hhhubh)”}”(hhh]”hŒChinese (Traditional)”…””}”hh2sbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ6/translations/zh_TW/driver-api/firmware/firmware_cache”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒItalian”…””}”hhFsbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ6/translations/it_IT/driver-api/firmware/firmware_cache”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒJapanese”…””}”hhZsbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ6/translations/ja_JP/driver-api/firmware/firmware_cache”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒKorean”…””}”hhnsbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ6/translations/ko_KR/driver-api/firmware/firmware_cache”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒSpanish”…””}”hh‚sbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ6/translations/sp_SP/driver-api/firmware/firmware_cache”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubeh}”(h]”h ]”h"]”h$]”h&]”Œcurrent_language”ŒEnglish”uh1h
hhŒ	_document”hŒsource”NŒline”NubhŒsection”“”)”}”(hhh]”(hŒtitle”“”)”}”(hŒFirmware cache”h]”hŒFirmware cache”…””}”(hh¨hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¦hh£hžhhŸŒP/var/lib/git/docbuild/linux/Documentation/driver-api/firmware/firmware_cache.rst”h KubhŒ	paragraph”“”)”}”(hX6  When Linux resumes from suspend some device drivers require firmware lookups to
re-initialize devices. During resume there may be a period of time during which
firmware lookups are not possible, during this short period of time firmware
requests will fail. Time is of essence though, and delaying drivers to wait for
the root filesystem for firmware delays user experience with device
functionality. In order to support these requirements the firmware
infrastructure implements a firmware cache for device drivers for most API
calls, automatically behind the scenes.”h]”hX6  When Linux resumes from suspend some device drivers require firmware lookups to
re-initialize devices. During resume there may be a period of time during which
firmware lookups are not possible, during this short period of time firmware
requests will fail. Time is of essence though, and delaying drivers to wait for
the root filesystem for firmware delays user experience with device
functionality. In order to support these requirements the firmware
infrastructure implements a firmware cache for device drivers for most API
calls, automatically behind the scenes.”…””}”(hh¹hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h Khh£hžhubh¸)”}”(hŒìThe firmware cache makes using certain firmware API calls safe during a device
driver's suspend and resume callback.  Users of these API calls needn't cache
the firmware by themselves for dealing with firmware loss during system resume.”h]”hŒðThe firmware cache makes using certain firmware API calls safe during a device
driverâ€™s suspend and resume callback.  Users of these API calls neednâ€™t cache
the firmware by themselves for dealing with firmware loss during system resume.”…””}”(hhÇhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h Khh£hžhubh¸)”}”(hXG  The firmware cache works by requesting for firmware prior to suspend and
caching it in memory. Upon resume device drivers using the firmware API will
have access to the firmware immediately, without having to wait for the root
filesystem to mount or dealing with possible race issues with lookups as the
root filesystem mounts.”h]”hXG  The firmware cache works by requesting for firmware prior to suspend and
caching it in memory. Upon resume device drivers using the firmware API will
have access to the firmware immediately, without having to wait for the root
filesystem to mount or dealing with possible race issues with lookups as the
root filesystem mounts.”…””}”(hhÕhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h Khh£hžhubh¸)”}”(hŒ;Some implementation details about the firmware cache setup:”h]”hŒ;Some implementation details about the firmware cache setup:”…””}”(hhãhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h Khh£hžhubhŒbullet_list”“”)”}”(hhh]”(hŒ	list_item”“”)”}”(hŒThe firmware cache is setup by adding a devres entry for each device that
uses all synchronous call except :c:func:`request_firmware_into_buf`.
”h]”h¸)”}”(hŒThe firmware cache is setup by adding a devres entry for each device that
uses all synchronous call except :c:func:`request_firmware_into_buf`.”h]”(hŒkThe firmware cache is setup by adding a devres entry for each device that
uses all synchronous call except ”…””}”(hhühžhhŸNh Nubh)”}”(hŒ#:c:func:`request_firmware_into_buf`”h]”hŒliteral”“”)”}”(hj  h]”hŒrequest_firmware_into_buf()”…””}”(hj
  hžhhŸNh Nubah}”(h]”h ]”(Œxref”Œc”Œc-func”eh"]”h$]”h&]”uh1j  hj  ubah}”(h]”h ]”h"]”h$]”h&]”Œrefdoc”Œ"driver-api/firmware/firmware_cache”Œ	refdomain”j  Œreftype”Œfunc”Œrefexplicit”‰Œrefwarn”‰Œ	reftarget”Œrequest_firmware_into_buf”uh1hhŸh¶h KhhüubhŒ.”…””}”(hhühžhhŸNh Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h Khhøubah}”(h]”h ]”h"]”h$]”h&]”uh1höhhóhžhhŸh¶h Nubh÷)”}”(hXA  If an asynchronous call is used the firmware cache is only set up for a
device if the second argument (uevent) to request_firmware_nowait() is
true. When uevent is true it requests that a kobject uevent be sent to
userspace for the firmware request through the sysfs fallback mechanism
if the firmware file is not found.
”h]”h¸)”}”(hX@  If an asynchronous call is used the firmware cache is only set up for a
device if the second argument (uevent) to request_firmware_nowait() is
true. When uevent is true it requests that a kobject uevent be sent to
userspace for the firmware request through the sysfs fallback mechanism
if the firmware file is not found.”h]”hX@  If an asynchronous call is used the firmware cache is only set up for a
device if the second argument (uevent) to request_firmware_nowait() is
true. When uevent is true it requests that a kobject uevent be sent to
userspace for the firmware request through the sysfs fallback mechanism
if the firmware file is not found.”…””}”(hj=  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h Khj9  ubah}”(h]”h ]”h"]”h$]”h&]”uh1höhhóhžhhŸh¶h Nubh÷)”}”(hŒ°If the firmware cache is determined to be needed as per the above two
criteria the firmware cache is setup by adding a devres entry for the
device making the firmware request.
”h]”h¸)”}”(hŒ¯If the firmware cache is determined to be needed as per the above two
criteria the firmware cache is setup by adding a devres entry for the
device making the firmware request.”h]”hŒ¯If the firmware cache is determined to be needed as per the above two
criteria the firmware cache is setup by adding a devres entry for the
device making the firmware request.”…””}”(hjU  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K#hjQ  ubah}”(h]”h ]”h"]”h$]”h&]”uh1höhhóhžhhŸh¶h Nubh÷)”}”(hŒ¼The firmware devres entry is maintained throughout the lifetime of the
device. This means that even if you release_firmware() the firmware cache
will still be used on resume from suspend.
”h]”h¸)”}”(hŒ»The firmware devres entry is maintained throughout the lifetime of the
device. This means that even if you release_firmware() the firmware cache
will still be used on resume from suspend.”h]”hŒ»The firmware devres entry is maintained throughout the lifetime of the
device. This means that even if you release_firmware() the firmware cache
will still be used on resume from suspend.”…””}”(hjm  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K'hji  ubah}”(h]”h ]”h"]”h$]”h&]”uh1höhhóhžhhŸh¶h Nubh÷)”}”(hŒÓThe timeout for the fallback mechanism is temporarily reduced to 10 seconds
as the firmware cache is set up during suspend, the timeout is set back to
the old value you had configured after the cache is set up.
”h]”h¸)”}”(hŒÒThe timeout for the fallback mechanism is temporarily reduced to 10 seconds
as the firmware cache is set up during suspend, the timeout is set back to
the old value you had configured after the cache is set up.”h]”hŒÒThe timeout for the fallback mechanism is temporarily reduced to 10 seconds
as the firmware cache is set up during suspend, the timeout is set back to
the old value you had configured after the cache is set up.”…””}”(hj…  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K+hj  ubah}”(h]”h ]”h"]”h$]”h&]”uh1höhhóhžhhŸh¶h Nubh÷)”}”(hX$  Upon suspend any pending non-uevent firmware requests are killed to avoid
stalling the kernel, this is done with kill_requests_without_uevent(). Kernel
calls requiring the non-uevent therefore need to implement their own firmware
cache mechanism but must not use the firmware API on suspend.
”h]”h¸)”}”(hX#  Upon suspend any pending non-uevent firmware requests are killed to avoid
stalling the kernel, this is done with kill_requests_without_uevent(). Kernel
calls requiring the non-uevent therefore need to implement their own firmware
cache mechanism but must not use the firmware API on suspend.”h]”hX#  Upon suspend any pending non-uevent firmware requests are killed to avoid
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calls requiring the non-uevent therefore need to implement their own firmware
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