<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-toradex.git/include/acpi/video.h, branch v4.4.5</title>
<subtitle>Linux kernel for Apalis and Colibri modules</subtitle>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/'/>
<entry>
<title>ACPI: Eliminate CONFIG_.*{, _MODULE} #ifdef in favor of IS_ENABLED()</title>
<updated>2015-09-15T01:05:45+00:00</updated>
<author>
<name>Sudeep Holla</name>
<email>Sudeep.Holla@arm.com</email>
</author>
<published>2015-09-14T15:01:55+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=bcb2b0b2bae2de744223c68521cd51c57feb486c'/>
<id>bcb2b0b2bae2de744223c68521cd51c57feb486c</id>
<content type='text'>
This commit removes all CONFIG_.*{,_MODULE} in ACPI code, replacing it
with IS_ENABLED().

Signed-off-by: Sudeep Holla &lt;sudeep.holla@arm.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
This commit removes all CONFIG_.*{,_MODULE} in ACPI code, replacing it
with IS_ENABLED().

Signed-off-by: Sudeep Holla &lt;sudeep.holla@arm.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ACPI / video: Inline acpi_video_set_dmi_backlight_type</title>
<updated>2015-06-24T17:59:28+00:00</updated>
<author>
<name>Borislav Petkov</name>
<email>bp@suse.de</email>
</author>
<published>2015-06-24T10:01:49+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=eddda195dd9272224a8e6112881829ed74ffef5b'/>
<id>eddda195dd9272224a8e6112881829ed74ffef5b</id>
<content type='text'>
... and kill this:

  In file included from drivers/gpu/drm/radeon/radeon_acpi.c:29:0:
  include/acpi/video.h:46:13: warning: ‘acpi_video_set_dmi_backlight_type’ defined but not used [-Wunused-function]
   static void acpi_video_set_dmi_backlight_type(enum acpi_backlight_type type)
               ^

Signed-off-by: Borislav Petkov &lt;bp@suse.de&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
... and kill this:

  In file included from drivers/gpu/drm/radeon/radeon_acpi.c:29:0:
  include/acpi/video.h:46:13: warning: ‘acpi_video_set_dmi_backlight_type’ defined but not used [-Wunused-function]
   static void acpi_video_set_dmi_backlight_type(enum acpi_backlight_type type)
               ^

Signed-off-by: Borislav Petkov &lt;bp@suse.de&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ACPI / video: Make acpi_video_unregister_backlight() private</title>
<updated>2015-06-18T23:12:50+00:00</updated>
<author>
<name>Hans de Goede</name>
<email>hdegoede@redhat.com</email>
</author>
<published>2015-06-16T14:28:13+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=e7d024c00a4a7b617390db863bdd5b9dc65821f7'/>
<id>e7d024c00a4a7b617390db863bdd5b9dc65821f7</id>
<content type='text'>
acpi_video_unregister_backlight() is now only used by video_detect.c
which is part of the same acpi_video module as video.c, make
acpi_video_unregister_backlight() private to this module.

Signed-off-by: Hans de Goede &lt;hdegoede@redhat.com&gt;
Acked-by: Darren Hart &lt;dvhart@linux.intel.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
acpi_video_unregister_backlight() is now only used by video_detect.c
which is part of the same acpi_video module as video.c, make
acpi_video_unregister_backlight() private to this module.

Signed-off-by: Hans de Goede &lt;hdegoede@redhat.com&gt;
Acked-by: Darren Hart &lt;dvhart@linux.intel.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ACPI / video: Port to new backlight interface selection API</title>
<updated>2015-06-18T23:10:59+00:00</updated>
<author>
<name>Hans de Goede</name>
<email>hdegoede@redhat.com</email>
</author>
<published>2015-06-16T14:27:51+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=3bd6bce36975f571cb47fa9d0aac9e06f94f4028'/>
<id>3bd6bce36975f571cb47fa9d0aac9e06f94f4028</id>
<content type='text'>
Most of the patch is moving the dmi quirks for forcing use of the
acpi-video / the native backlight interface to video_detect.c.

What remains is a nice cleanup.

Signed-off-by: Hans de Goede &lt;hdegoede@redhat.com&gt;
Acked-by: Darren Hart &lt;dvhart@linux.intel.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Most of the patch is moving the dmi quirks for forcing use of the
acpi-video / the native backlight interface to video_detect.c.

What remains is a nice cleanup.

Signed-off-by: Hans de Goede &lt;hdegoede@redhat.com&gt;
Acked-by: Darren Hart &lt;dvhart@linux.intel.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>acpi-video-detect: Rewrite backlight interface selection logic</title>
<updated>2015-06-18T23:10:44+00:00</updated>
<author>
<name>Hans de Goede</name>
<email>hdegoede@redhat.com</email>
</author>
<published>2015-06-16T14:27:48+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=87521e16a7abbf3fa337f56cb4d1e18247f15e8a'/>
<id>87521e16a7abbf3fa337f56cb4d1e18247f15e8a</id>
<content type='text'>
Currently we have 2 kernel commandline options + dmi-quirks in 3 places all
interacting (in interesting ways) to select which which backlight interface
to use. On the commandline we've acpi_backlight=[video|vendor] and
video.use_native_backlight=[0|1]. DMI quirks we have in
acpi/video-detect.c, acpi/video.c and drivers/platform/x86/*.c .

This commit is the first step to cleaning this up, replacing the 2 cmdline
options with just acpi_backlight=[video|vendor|native|none], and adds a
new API to video_detect.c to reflect this.

Follow up commits will also move other related code, like unregistering the
acpi_video backlight interface if it was registered before other drivers
which take priority over it are loaded, to video_detect.c where this
logic really belongs.

Signed-off-by: Hans de Goede &lt;hdegoede@redhat.com&gt;
Acked-by: Darren Hart &lt;dvhart@linux.intel.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Currently we have 2 kernel commandline options + dmi-quirks in 3 places all
interacting (in interesting ways) to select which which backlight interface
to use. On the commandline we've acpi_backlight=[video|vendor] and
video.use_native_backlight=[0|1]. DMI quirks we have in
acpi/video-detect.c, acpi/video.c and drivers/platform/x86/*.c .

This commit is the first step to cleaning this up, replacing the 2 cmdline
options with just acpi_backlight=[video|vendor|native|none], and adds a
new API to video_detect.c to reflect this.

Follow up commits will also move other related code, like unregistering the
acpi_video backlight interface if it was registered before other drivers
which take priority over it are loaded, to video_detect.c where this
logic really belongs.

Signed-off-by: Hans de Goede &lt;hdegoede@redhat.com&gt;
Acked-by: Darren Hart &lt;dvhart@linux.intel.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ACPI / i915: ignore firmware requests for backlight change</title>
<updated>2014-07-07T21:38:05+00:00</updated>
<author>
<name>Aaron Lu</name>
<email>aaron.lu@intel.com</email>
</author>
<published>2014-07-07T07:43:51+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=0b9f7d93ca6109048a4eb06332b666b6e29df4fe'/>
<id>0b9f7d93ca6109048a4eb06332b666b6e29df4fe</id>
<content type='text'>
Some Thinkpad laptops' firmware will initiate a backlight level change
request through operation region on the events of AC plug/unplug, but
since we are not using firmware's interface to do the backlight setting
on these affected laptops, we do not want the firmware to use some
arbitrary value from its ASL variable to set the backlight level on
AC plug/unplug either.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=76491
Link: https://bugzilla.kernel.org/show_bug.cgi?id=77091
Reported-and-tested-by: Igor Gnatenko &lt;i.gnatenko.brain@gmail.com&gt;
Reported-and-tested-by: Anton Gubarkov &lt;anton.gubarkov@gmail.com&gt;
Signed-off-by: Aaron Lu &lt;aaron.lu@intel.com&gt;
Acked-by: Jani Nikula &lt;jani.nikula@intel.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Some Thinkpad laptops' firmware will initiate a backlight level change
request through operation region on the events of AC plug/unplug, but
since we are not using firmware's interface to do the backlight setting
on these affected laptops, we do not want the firmware to use some
arbitrary value from its ASL variable to set the backlight level on
AC plug/unplug either.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=76491
Link: https://bugzilla.kernel.org/show_bug.cgi?id=77091
Reported-and-tested-by: Igor Gnatenko &lt;i.gnatenko.brain@gmail.com&gt;
Reported-and-tested-by: Anton Gubarkov &lt;anton.gubarkov@gmail.com&gt;
Signed-off-by: Aaron Lu &lt;aaron.lu@intel.com&gt;
Acked-by: Jani Nikula &lt;jani.nikula@intel.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ACPI / video: Add an acpi_video_unregister_backlight function</title>
<updated>2014-05-20T11:41:42+00:00</updated>
<author>
<name>Hans de Goede</name>
<email>hdegoede@redhat.com</email>
</author>
<published>2014-05-17T08:48:01+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=1b7f37e1276bee9043d35a4b39ef2f43d3b2e133'/>
<id>1b7f37e1276bee9043d35a4b39ef2f43d3b2e133</id>
<content type='text'>
Add an acpi_video_unregister_backlight function, which only unregisters
the backlight device, and leaves the acpi_notifier in place. Some acpi_vendor
driver need this as they don't want the acpi_video# backlight device, but do
need the acpi-video driver for hotkey handling.

Chances are that this new acpi_video_unregister_backlight() is actually
what existing acpi_vendor drivers have wanted all along. Currently acpi_vendor
drivers which want to disable the acpi_video# backlight device, make 2 calls:

acpi_video_dmi_promote_vendor();
acpi_video_unregister();

The intention here is to make things independent of when acpi_video_register()
gets called. As acpi_video_register() will get called on acpi-video load time
on non intel gfx machines, while it gets called on i915 load time on intel
gfx machines.

This leads to the following 2 interesting scenarios:

 a) intel gfx:
  1) acpi-video module gets loaded (as it is a dependency of acpi_vendor
     and i915)
  2) acpi-video does NOT call acpi_video_register()
  3) acpi_vendor loads (lets assume it loads before i915), calls
     acpi_video_dmi_promote_vendor(); which sets
     ACPI_VIDEO_BACKLIGHT_DMI_VENDOR
  4) calls acpi_video_unregister -&gt; not registered, nop
  5) i915 loads, calls acpi_video_register
  6) acpi_video_register registers the acpi_notifier for the hotkeys,
     does NOT register a backlight device because of
     ACPI_VIDEO_BACKLIGHT_DMI_VENDOR

 b) non intel gfx
  1) acpi-video module gets loaded (as it is a dependency acpi_vendor)
  2) acpi-video calls acpi_video_register()
  3) acpi_video_register registers the acpi_notifier for the hotkeys,
     and a backlight device
  4) acpi_vendor loads, calls acpi_video_dmi_promote_vendor()
  5) calls acpi_video_unregister, this unregisters BOTH the acpi_notifier
     for the hotkeys AND the backlight device

So here we have possibly the same acpi_vendor module, making the same calls,
but with different results, in one cases acpi-video does handle hotkeys,
in the other it does not.

Note that the a) scenario turns into b) if we assume the i915 module loads
before the vendor_acpi module, so we also have different behavior depending
on module loading order!

So as said I believe that quite a few existing acpi_vendor modules really
always want the behavior of a), hence this patch adds a new
acpi_video_unregister_backlight() which gives the behavior of a) independent
of module loading order.

Signed-off-by: Hans de Goede &lt;hdegoede@redhat.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Add an acpi_video_unregister_backlight function, which only unregisters
the backlight device, and leaves the acpi_notifier in place. Some acpi_vendor
driver need this as they don't want the acpi_video# backlight device, but do
need the acpi-video driver for hotkey handling.

Chances are that this new acpi_video_unregister_backlight() is actually
what existing acpi_vendor drivers have wanted all along. Currently acpi_vendor
drivers which want to disable the acpi_video# backlight device, make 2 calls:

acpi_video_dmi_promote_vendor();
acpi_video_unregister();

The intention here is to make things independent of when acpi_video_register()
gets called. As acpi_video_register() will get called on acpi-video load time
on non intel gfx machines, while it gets called on i915 load time on intel
gfx machines.

This leads to the following 2 interesting scenarios:

 a) intel gfx:
  1) acpi-video module gets loaded (as it is a dependency of acpi_vendor
     and i915)
  2) acpi-video does NOT call acpi_video_register()
  3) acpi_vendor loads (lets assume it loads before i915), calls
     acpi_video_dmi_promote_vendor(); which sets
     ACPI_VIDEO_BACKLIGHT_DMI_VENDOR
  4) calls acpi_video_unregister -&gt; not registered, nop
  5) i915 loads, calls acpi_video_register
  6) acpi_video_register registers the acpi_notifier for the hotkeys,
     does NOT register a backlight device because of
     ACPI_VIDEO_BACKLIGHT_DMI_VENDOR

 b) non intel gfx
  1) acpi-video module gets loaded (as it is a dependency acpi_vendor)
  2) acpi-video calls acpi_video_register()
  3) acpi_video_register registers the acpi_notifier for the hotkeys,
     and a backlight device
  4) acpi_vendor loads, calls acpi_video_dmi_promote_vendor()
  5) calls acpi_video_unregister, this unregisters BOTH the acpi_notifier
     for the hotkeys AND the backlight device

So here we have possibly the same acpi_vendor module, making the same calls,
but with different results, in one cases acpi-video does handle hotkeys,
in the other it does not.

Note that the a) scenario turns into b) if we assume the i915 module loads
before the vendor_acpi module, so we also have different behavior depending
on module loading order!

So as said I believe that quite a few existing acpi_vendor modules really
always want the behavior of a), hence this patch adds a new
acpi_video_unregister_backlight() which gives the behavior of a) independent
of module loading order.

Signed-off-by: Hans de Goede &lt;hdegoede@redhat.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Revert "ACPI / video / i915: No ACPI backlight if firmware expects Windows 8"</title>
<updated>2013-07-26T12:59:20+00:00</updated>
<author>
<name>Rafael J. Wysocki</name>
<email>rafael.j.wysocki@intel.com</email>
</author>
<published>2013-07-25T19:43:39+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=8e5c2b776ae4c35f54547c017e0a943429f5748a'/>
<id>8e5c2b776ae4c35f54547c017e0a943429f5748a</id>
<content type='text'>
We attempted to address a regression introduced by commit a57f7f9
(ACPICA: Add Windows8/Server2012 string for _OSI method.) after which
ACPI video backlight support doesn't work on a number of systems,
because the relevant AML methods in the ACPI tables in their BIOSes
become useless after the BIOS has been told that the OS is compatible
with Windows 8.  That problem is tracked by the bug entry at:

https://bugzilla.kernel.org/show_bug.cgi?id=51231

Commit 8c5bd7a (ACPI / video / i915: No ACPI backlight if firmware
expects Windows 8) introduced for this purpose essentially prevented
the ACPI backlight support from being used if the BIOS had been told
that the OS was compatible with Windows 8 and the i915 driver was
loaded, in which case the backlight would always be handled by i915.
Unfortunately, however, that turned out to cause problems with
backlight to appear on multiple systems with symptoms indicating that
i915 was unable to control the backlight on those systems as
expected.

For this reason, revert commit 8c5bd7a, but leave the function
acpi_video_backlight_quirks() introduced by it, because another
commit on top of it uses that function.

References: https://lkml.org/lkml/2013/7/21/119
References: https://lkml.org/lkml/2013/7/22/261
References: https://lkml.org/lkml/2013/7/23/429
References: https://lkml.org/lkml/2013/7/23/459
References: https://lkml.org/lkml/2013/7/23/81
References: https://lkml.org/lkml/2013/7/24/27
Reported-and-tested-by: James Hogan &lt;james@albanarts.com&gt;
Reported-and-tested-by: Kamal Mostafa &lt;kamal@canonical.com&gt;
Reported-and-tested-by: Jörg Otte &lt;jrg.otte@gmail.com&gt;
Reported-and-tested-by: Steven Newbury &lt;steve@snewbury.org.uk&gt;
Reported-by: Martin Steigerwald &lt;Martin@lichtvoll.de&gt;
Reported-by: Kalle Valo &lt;kvalo@adurom.com&gt;
Tested-by: Joerg Platte &lt;jplatte@naasa.net&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
We attempted to address a regression introduced by commit a57f7f9
(ACPICA: Add Windows8/Server2012 string for _OSI method.) after which
ACPI video backlight support doesn't work on a number of systems,
because the relevant AML methods in the ACPI tables in their BIOSes
become useless after the BIOS has been told that the OS is compatible
with Windows 8.  That problem is tracked by the bug entry at:

https://bugzilla.kernel.org/show_bug.cgi?id=51231

Commit 8c5bd7a (ACPI / video / i915: No ACPI backlight if firmware
expects Windows 8) introduced for this purpose essentially prevented
the ACPI backlight support from being used if the BIOS had been told
that the OS was compatible with Windows 8 and the i915 driver was
loaded, in which case the backlight would always be handled by i915.
Unfortunately, however, that turned out to cause problems with
backlight to appear on multiple systems with symptoms indicating that
i915 was unable to control the backlight on those systems as
expected.

For this reason, revert commit 8c5bd7a, but leave the function
acpi_video_backlight_quirks() introduced by it, because another
commit on top of it uses that function.

References: https://lkml.org/lkml/2013/7/21/119
References: https://lkml.org/lkml/2013/7/22/261
References: https://lkml.org/lkml/2013/7/23/429
References: https://lkml.org/lkml/2013/7/23/459
References: https://lkml.org/lkml/2013/7/23/81
References: https://lkml.org/lkml/2013/7/24/27
Reported-and-tested-by: James Hogan &lt;james@albanarts.com&gt;
Reported-and-tested-by: Kamal Mostafa &lt;kamal@canonical.com&gt;
Reported-and-tested-by: Jörg Otte &lt;jrg.otte@gmail.com&gt;
Reported-and-tested-by: Steven Newbury &lt;steve@snewbury.org.uk&gt;
Reported-by: Martin Steigerwald &lt;Martin@lichtvoll.de&gt;
Reported-by: Kalle Valo &lt;kvalo@adurom.com&gt;
Tested-by: Joerg Platte &lt;jplatte@naasa.net&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ACPI / video / i915: No ACPI backlight if firmware expects Windows 8</title>
<updated>2013-07-18T00:08:06+00:00</updated>
<author>
<name>Rafael J. Wysocki</name>
<email>rafael.j.wysocki@intel.com</email>
</author>
<published>2013-07-18T00:08:06+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=8c5bd7adb2ce47e6aa39d17b2375f69b0c0aa255'/>
<id>8c5bd7adb2ce47e6aa39d17b2375f69b0c0aa255</id>
<content type='text'>
According to Matthew Garrett, "Windows 8 leaves backlight control up
to individual graphics drivers rather than making ACPI calls itself.
There's plenty of evidence to suggest that the Intel driver for
Windows [8] doesn't use the ACPI interface, including the fact that
it's broken on a bunch of machines when the OS claims to support
Windows 8.  The simplest thing to do appears to be to disable the
ACPI backlight interface on these systems".

There's a problem with that approach, however, because simply
avoiding to register the ACPI backlight interface if the firmware
calls _OSI for Windows 8 may not work in the following situations:
 (1) The ACPI backlight interface actually works on the given system
     and the i915 driver is not loaded (e.g. another graphics driver
     is used).
 (2) The ACPI backlight interface doesn't work on the given system,
     but there is a vendor platform driver that will register its
     own, equally broken, backlight interface if not prevented from
     doing so by the ACPI subsystem.
Therefore we need to allow the ACPI backlight interface to be
registered until the i915 driver is loaded which then will unregister
it if the firmware has called _OSI for Windows 8 (or will register
the ACPI video driver without backlight support if not already
present).

For this reason, introduce an alternative function for registering
ACPI video, acpi_video_register_with_quirks(), that will check
whether or not the ACPI video driver has already been registered
and whether or not the backlight Windows 8 quirk has to be applied.
If the quirk has to be applied, it will block the ACPI backlight
support and either unregister the backlight interface if the ACPI
video driver has already been registered, or register the ACPI
video driver without the backlight interface otherwise.  Make
the i915 driver use acpi_video_register_with_quirks() instead of
acpi_video_register() in i915_driver_load().

This change is based on earlier patches from Matthew Garrett,
Chun-Yi Lee and Seth Forshee and includes a fix from Aaron Lu's.

References: https://bugzilla.kernel.org/show_bug.cgi?id=51231
Tested-by: Aaron Lu &lt;aaron.lu@intel.com&gt;
Tested-by: Igor Gnatenko &lt;i.gnatenko.brain@gmail.com&gt;
Tested-by: Yves-Alexis Perez &lt;corsac@debian.org&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Reviewed-by: Aaron Lu &lt;aaron.lu@intel.com&gt;
Acked-by: Matthew Garrett &lt;matthew.garrett@nebula.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
According to Matthew Garrett, "Windows 8 leaves backlight control up
to individual graphics drivers rather than making ACPI calls itself.
There's plenty of evidence to suggest that the Intel driver for
Windows [8] doesn't use the ACPI interface, including the fact that
it's broken on a bunch of machines when the OS claims to support
Windows 8.  The simplest thing to do appears to be to disable the
ACPI backlight interface on these systems".

There's a problem with that approach, however, because simply
avoiding to register the ACPI backlight interface if the firmware
calls _OSI for Windows 8 may not work in the following situations:
 (1) The ACPI backlight interface actually works on the given system
     and the i915 driver is not loaded (e.g. another graphics driver
     is used).
 (2) The ACPI backlight interface doesn't work on the given system,
     but there is a vendor platform driver that will register its
     own, equally broken, backlight interface if not prevented from
     doing so by the ACPI subsystem.
Therefore we need to allow the ACPI backlight interface to be
registered until the i915 driver is loaded which then will unregister
it if the firmware has called _OSI for Windows 8 (or will register
the ACPI video driver without backlight support if not already
present).

For this reason, introduce an alternative function for registering
ACPI video, acpi_video_register_with_quirks(), that will check
whether or not the ACPI video driver has already been registered
and whether or not the backlight Windows 8 quirk has to be applied.
If the quirk has to be applied, it will block the ACPI backlight
support and either unregister the backlight interface if the ACPI
video driver has already been registered, or register the ACPI
video driver without the backlight interface otherwise.  Make
the i915 driver use acpi_video_register_with_quirks() instead of
acpi_video_register() in i915_driver_load().

This change is based on earlier patches from Matthew Garrett,
Chun-Yi Lee and Seth Forshee and includes a fix from Aaron Lu's.

References: https://bugzilla.kernel.org/show_bug.cgi?id=51231
Tested-by: Aaron Lu &lt;aaron.lu@intel.com&gt;
Tested-by: Igor Gnatenko &lt;i.gnatenko.brain@gmail.com&gt;
Tested-by: Yves-Alexis Perez &lt;corsac@debian.org&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Reviewed-by: Aaron Lu &lt;aaron.lu@intel.com&gt;
Acked-by: Matthew Garrett &lt;matthew.garrett@nebula.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>i915: Fix opregion notifications</title>
<updated>2011-07-13T18:19:47+00:00</updated>
<author>
<name>Matthew Garrett</name>
<email>mjg@redhat.com</email>
</author>
<published>2011-07-12T22:30:52+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=f5a3d0c4086d1854cbda545092c462b84cba20ce'/>
<id>f5a3d0c4086d1854cbda545092c462b84cba20ce</id>
<content type='text'>
opregion-based platforms will send ACPI video event 0x80 for a range of
notification types for legacy compatibility. This is interpreted as a
display switch event, which may not be appropriate in the circumstances.
When we receive such an event we should make sure that the platform is
genuinely requesting a display switch before passing that event through
to userspace.

Signed-off-by: Matthew Garrett &lt;mjg@redhat.com&gt;
Tested-by: Adam Jackson &lt;ajax@redhat.com&gt;
Signed-off-by: Keith Packard &lt;keithp@keithp.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
opregion-based platforms will send ACPI video event 0x80 for a range of
notification types for legacy compatibility. This is interpreted as a
display switch event, which may not be appropriate in the circumstances.
When we receive such an event we should make sure that the platform is
genuinely requesting a display switch before passing that event through
to userspace.

Signed-off-by: Matthew Garrett &lt;mjg@redhat.com&gt;
Tested-by: Adam Jackson &lt;ajax@redhat.com&gt;
Signed-off-by: Keith Packard &lt;keithp@keithp.com&gt;
</pre>
</div>
</content>
</entry>
</feed>
