Just like many other Samsung models, the 670Z5E needs to use the acpi-video
backlight interface rather then the native one for backlight control to
work, add a quirk for this.

Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=1557060
Cc: All applicable <stable@vger.kernel.org>
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Dell OptiPlex 9020M is a micro PC desktop that has no built-in
LCD panel and its acpi_video does not work.
Signed-off-by: NAlex Hung <alex.hung@canonical.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

The Dell Precision 7510 has a broken acpi-video implementation.

The backlight control bits work, but when the brightness is changed via
the acpi-video interface the backlight flickers annoyingly before settling
at the new brightness, switching to using the native interface fixes the
flickering so add a quirk for this (the vendor interface can not change the
brightness at all).
Signed-off-by: NShih-Yuan Lee (FourDollars) <sylee@canonical.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Revert commit 6276e53f (ACPI / video: Add force_native quirk for
HP Pavilion dv6).

In the commit message for the quirk this revert removes I wrote:

"Note that there are quite a few HP Pavilion dv6 variants, some
woth ATI and some with NVIDIA hybrid gfx, both seem to need this
quirk to have working backlight control. There are also some versions
with only Intel integrated gfx, these may not need this quirk, but it
should not hurt there."

Unfortunately that seems wrong, I've already received 2 reports of
this commit causing regressions on some dv6 variants (at least one
of which actually has a nvidia GPU). So it seems that HP has made a
mess here by using the same model-name both in marketing and in the
DMI data for many different variants. Some of which need
acpi_backlight=native for functional backlight control (as the
quirk this commit reverts was doing), where as others are broken by
it. So lets get back to the old sitation so as to avoid regressing
on models which used to work without any kernel cmdline arguments
before.

Fixes: 6276e53f (ACPI / video: Add force_native quirk for HP Pavilion dv6)
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

The HP Pavilion dv6 has a non-working acpi_video0 backlight interface
and an intel_backlight interface which works fine. Add a force_native
quirk for it so that the non-working acpi_video0 interface does not get
registered.

Note that there are quite a few HP Pavilion dv6 variants, some
woth ATI and some with NVIDIA hybrid gfx, both seem to need this
quirk to have working backlight control. There are also some versions
with only Intel integrated gfx, these may not need this quirk, but it
should not hurt there.

Link: https://bugzilla.redhat.com/show_bug.cgi?id=1204476
Link: https://bugs.launchpad.net/ubuntu/+source/linux-lts-trusty/+bug/1416940
Cc: All applicable <stable@vger.kernel.org>
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

The Dell XPS 17 L702X has a non-working acpi_video0 backlight interface
and an intel_backlight interface which works fine. Add a force_native
quirk for it so that the non-working acpi_video0 interface does not get
registered.

Note that there also is an issue with the brightnesskeys on this laptop,
they do not generate key-press events in anyway. That is not solved by
this patch.

Link: https://bugzilla.redhat.com/show_bug.cgi?id=1123661
Cc: All applicable <stable@vger.kernel.org>
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Add Thinkpad X201 Tablet to the video_detect_force_video blacklist.
Signed-off-by: NRalf Gerbig <rge@quengel.org>
[ rjw : Changelog ]
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Since we will need the backlight_device_get_by_type API, we can use it
instead of the backlight_device_registered API whenever necessary so
remove the backlight_device_registered API.
Signed-off-by: NAaron Lu <aaron.lu@intel.com>
Acked-by: NJingoo Han <jg1.han@samsung.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

The quirk to get "acpi_backlight=vendor" behavior by default on the
Dell Inspiron 5737 was added before we started doing
"acpi_backlight=native" by default on Win8 ready machines.

Since we now avoid using acpi-video as backlight driver on these machines
by default (using the native driver instead) we no longer need this quirk.

Moreover the vendor driver does not work after a suspend/resume where
as the native driver does.

This reverts commit 08a56226 (ACPI / video: Add Dell Inspiron 5737
to the blacklist).

Link: https://bugzilla.kernel.org/show_bug.cgi?id=111061
Cc: 3.19+ <stable@vger.kernel.org> # 3.19+
Reported-and-tested-by: erusan@gmail.com
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

The native interface on SAMSUNG 530U4E/540U4E doesn't work even though
the firmware claims Win8 compatible while the acpi_video interface
works, add a quirk for this.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=108971Reported-and-tested-by: Nadam bk <adamdd55@gmail.com>
Signed-off-by: NAaron Lu <aaron.lu@intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

The Dell Vostro V131 has an especially broken acpi-video implementation.

The backlight control bits work, but when the brightness is changed via
the acpi-video interface the backlight flickers annoyingly before settling
at the new brightness, switching to using the native interface fixes the
flickering so add a quirk for this (the vendor interface has the same
problem).

Brightness keypresses reported through the acpi-video-bus are also broken,
they get reported one event delayed, so if you press the brightness-up
hotkey on the keyboard nothing happens, then if you press brightness-down,
the previous brightness-up event gets reported. Since the keypresses are
also reported via wmi (if active) and via atkbd (when wmi is not active)
add a quirk to simply filter out the delayed (broken) events.
Reported-and-tested-by: NMichał Kępień <kernel@kempniu.pl>
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Just like the Dell XPS 15 (L521X) the Dell XPS 14 (L421X) needs to use
the acpi-video backlight interface rather then the native one for backlight
control to work, add a quirk for this.

Link: https://bugzilla.redhat.com/show_bug.cgi?id=1272633Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

The Lenovo IdeaPad S405 is a not "Windows8 ready" machine which still has
a broken ACPI video backlight implementation. Add a quirk to force use
of native backlight on this machine.

Link: https://bugzilla.redhat.com/show_bug.cgi?id=1201530Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Before this commit, the following would happen:

 a) acpi_video_get_backlight_type() gets called
 b) acpi_video_get_backlight_type() calls acpi_video_init_backlight_type()
 c) acpi_video_init_backlight_type() locks its function static init_mutex
 d) acpi_video_init_backlight_type() calls backlight_register_notifier()
 e) backlight_register_notifier() takes its notifier-chain lock

And when the backlight notifier chain gets called we've:

 1) blocking_notifier_call_chain() gets called
 2) blocking_notifier_call_chain() takes the notifier-chain lock
 3) blocking_notifier_call_chain() calls acpi_video_backlight_notify()
 4) acpi_video_backlight_notify() calls acpi_video_get_backlight_type()
 5) acpi_video_get_backlight_type() calls acpi_video_init_backlight_type()
 6) acpi_video_init_backlight_type() locks its function static init_mutex

So in the first call sequence we have:

 a) init_mutex gets locked
 b) notifier-chain gets locked

and in the second call sequence we have:

 1) notifier-chain gets locked
 2) init_mutex gets locked

And we've a circular locking dependency. This specific locking dependency
is fixable without using the big hammer otherwise known as a workqueue,
but further analysis shows a similar problem with the backlight notifier
chain lock vs register_count_mutex from drivers/acpi/acpi_video.c,
and fixing that becomes problematic.

So this commit simply fixes this with the big hammer, performance
wise this is a non issue as we expect the work to get scheduled
exactly zero or one times during normal system use.

Fixes: 93a291df (ACPI / video: Move backlight notifier to video_detect.c)
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Reported-and-tested-by: NSedat Dilek <sedat.dilek@gmail.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

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: NHans de Goede <hdegoede@redhat.com>
Acked-by: NDarren Hart <dvhart@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Remove the old backlight interface selection API now that all drivers
have been ported to the new API.
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Acked-by: NDarren Hart <dvhart@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Move the unregistering of the acpi backlight interface on registering of a
native backlight from video.c to video_detect.c where it belongs.

Note this removes support for re-registering the acpi backlight interface
when the native interface goes away. In practice this never happens and
it needlessly complicates the code.
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Acked-by: NDarren Hart <dvhart@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

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: NHans de Goede <hdegoede@redhat.com>
Acked-by: NDarren Hart <dvhart@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Make acpi_video_set_dmi_backlight_type() call
acpi_video_unregister_backlight() when the new dmi quirk results in
the desired backlight interface being of a type other then
acpi_backlight_video.

This avoid the need for the second if in the following construction
which is currently found in many platform/x86 drivers:

	if (prefer_vendor_quirk)
		acpi_video_dmi_promote_vendor();

	if (!acpi_video_backlight_support())
		acpi_video_unregister_backlight()

This second if-block will be removed from the platform drivers as part
of their conversion to the new backlight interface selection API.
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Acked-by: NDarren Hart <dvhart@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

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: NHans de Goede <hdegoede@redhat.com>
Acked-by: NDarren Hart <dvhart@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

This is a preparation patch for the backlight interface selection logic
cleanup, there are 2 reasons to not always build the video_detect code
into the kernel:

1) In order for the video_detect.c to also deal with / select native
backlight interfaces on win8 systems, instead of doing this in video.c
where it does not belong, video_detect.c needs to call into the backlight
class code. Which cannot be done if it is builtin and the blacklight class
is not.

2) Currently all the platform/x86 drivers which have quirks to prefer
the vendor driver over acpi-video call acpi_video_unregister_backlight()
to remove the acpi-video backlight interface, this logic really belongs
in video_detect.c, which will cause video_detect.c to depend on symbols of
video.c and video.c already depends on video_detect.c symbols, so they
really need to be a single module.

Note that this commits make 2 changes so as to maintain 100% kernel
commandline compatibility:

1) The __setup call for the acpi_backlight= handling is moved to
   acpi/util.c as __setup may only be used by code which is alwasy builtin
2) video.c is renamed to acpi_video.c so that it can be combined with
   video_detect.c into video.ko

This commit also makes changes to drivers/platform/x86/Kconfig to ensure
that drivers which use acpi_video_backlight_support() from video_detect.c,
will not be built-in when acpi_video is not built in. This also changes
some "select" uses to "depends on" to avoid dependency loops.
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Acked-by: NDarren Hart <dvhart@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

acpi_osi_is_win8 needs access to acpi_gbl_osi_data which is not exported,
so move it to osl.c. Alternatively we could export acpi_gbl_osi_data but
that seems undesirable.

This allows video_detect.c to be build as a module, besides that
acpi_osi_is_win8() is something which does not really belong in
video_detect.c in the first place.
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Acked-by: NDarren Hart <dvhart@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

This allows video_detect.c to be build as a module, this is a preparation
patch for the backlight interface selection logic cleanup.

Note this commit also causes acpi_is_video_device() to always be build
indepedent of CONFIG_ACPI_VIDEO, as there is no reason to make its
building depend on CONFIG_ACPI_VIDEO.
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Acked-by: NDarren Hart <dvhart@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

acpi_video_get_capabilities() is only used inside video_detect.c so make
it static. While at it also remove the prototype for the non existent
acpi_video_display_switch_support function from acpi.h
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Acked-by: NDarren Hart <dvhart@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Remove the now unused acpi_video_dmi_demote_vendor() function, this was
never a proper counter part of acpi_video_dmi_promote_vendor() since
the calls to acpi_video_dmi_promote_vendor() are not counted.
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Acked-by: NDarren Hart <dvhart@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Make the video ACPI device ID array static and constify the DMI system
IDs array.  Saves us a little bit of code.
Signed-off-by: NMathias Krause <minipli@googlemail.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

The Lenovo Ideapad Z570 (which is an Acer in disguise like some other Ideapads)
has a broken acpi_video interface, this was fixed in commmit a11d342f
("ACPI / video: force vendor backlight on Lenovo Ideapad Z570").

Which stops acpi_video from registering a backlight interface, but this is
only a partial fix, because for people who have the ideapad-laptop module
installed that module will now register a backlight interface, which also
does not work, so we need to use the native intel_backlight interface.

The Lenovo Ideapad 570 is a pre-win8 laptop / too old for the acpi-video code
to automatically prefer the native backlight interface, so add a quirk for it.

This commit also removes the previous incomplete fix.

Link: https://bugzilla.redhat.com/show_bug.cgi?id=1187004Tested-by: NBe <be.0@gmx.com>
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Lenovo Ideapad 570 is a pre-win8 laptop where not using vendor
backlight causes the backlight controls not to work.
Signed-off-by: NStepan Bujnak <stepanbujnak@fastmail.fm>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

With win8 capabiltiy, the ACPI backlight control is broken.
The system also loses backlight setting when resuming from S3.

Add this model to the the ACPI video detect blacklist to make backlight
functionality work.

Although backlight functionality works via video.use_native_backlight=1,
this approach may be safer.
Signed-off-by: NEdward Lin <yidi.lin@canonical.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

We already have a macro for PREFIX of "ACPI: " in
drivers/acpi/internal.h, so remove the duplicate ones
in ACPI drivers when internal.h is included.
Signed-off-by: NHanjun Guo <hanjun.guo@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Some system's ACPI video backlight control interface is broken and the
native backlight control interface should be used by default. This patch
sets the use_native_backlight parameter to true for those systems so
that video backlight control interface will not be created. For detailed
models that are added here, reference the following list.

Note that the user specified kernel cmdline option will always have the
highest priority, i.e. if use_native_backlight=0 is specified and the
system is in the DMI table, the video module will not skip registering
backlight interface for it.

Thinkpad T430s:
Reported-by: NTheodore Tso <tytso@mit.edu>
Reported-and-tested-by: NPeter Weber <bugs@ttyhoney.com>
References: https://bugzilla.kernel.org/show_bug.cgi?id=51231
Thinkpad X230:
Reported-and-tested-by: NIgor Gnatenko <i.gnatenko.brain@gmail.com>
References: https://bugzilla.kernel.org/show_bug.cgi?id=51231
ThinkPad X1 Carbon:
Reported-and-tested-by: NIgor Gnatenko <i.gnatenko.brain@gmail.com>
Lenovo Yoga 13:
Reported-by: NLennart Poettering <lennart@poettering.net>
Reported-and-tested-by: NKevin Smith <thirdwiggin@gmail.com>
References: https://bugzilla.kernel.org/show_bug.cgi?id=63811
Dell Inspiron 7520:
Reported-by: NRinat Ibragimov <ibragimovrinat@mail.ru>
Acer Aspire 5733Z:
Reported-by: <sov.info@mail.ru>
References: https://bugzilla.kernel.org/show_bug.cgi?id=62941
Acer Aspire V5-431:
Reported-by: NThomas Christensen <christensenthomas@gmail.com>
References: https://bugzilla.kernel.org/show_bug.cgi?id=68751
HP ProBook 4340s:
Reported-and-tested-by: NVladimir Sherenkov <a_12300@mail.ru>
References: http://redmine.russianfedora.pro/issues/1258
HP EliteBook/ProBook 2013 models, ZBook and some others:
Provided-by: NTakashi Iwai <tiwai@suse.de>
Signed-off-by: NAaron Lu <aaron.lu@intel.com>
Tested-by: NMika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

On HP EliteBook Revolve 810 the ACPI backlight device doesn't work as
expected. For example when resuming from system sleep, it seems to lose
backlight settings.

Forcing Intel driver fixes the problem so add this machine the ACPI
video detect blacklist.
Signed-off-by: NMika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Correct "**retyurn_value" to "**return_value".
Signed-off-by: NMasanari Iida <standby24x7@gmail.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

On the Yoga 13 the backlight control doesn't work via ACPI. (And doesn't
work either with the low-level platform driver ideapad_laptop; but
works correctly via the intel video driver).  This patch hence adds the
Yoga 13 to the ACPI video detect blacklist, to make sure the broken ACPI
backlight device is never exposed to userspace.

Note that this appears unrelated to the Windows 8 backlight issues tracked
here:

https://bugzilla.kernel.org/show_bug.cgi?id=51231
https://bugzilla.kernel.org/show_bug.cgi?id=60682

The Yoga's ACPI backlight controls work neither with nor without
acpi_osi="!Windows 2012" on the kernel command line. It appears that
backlight control via the EC simply is not available at all, regardless
whether done via ACPI or via the vendor driver.
Signed-off-by: NLennart Poettering <lennart@poettering.net>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

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".

So for Win8 systems, if there is native backlight control interface
registered by GPU driver, ACPI video does not need to register its own.
Since there are systems that don't work well with this approach, a
parameter for video module named use_native_backlight is introduced and
has the value of false by default. For users who have a broken ACPI
video backlight interface, video.use_native_backlight=1 is needed in
kernel cmdline.
Signed-off-by: NAaron Lu <aaron.lu@intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

We attempted to address a regression introduced by commit a57f7f91
(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 8c5bd7ad (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 8c5bd7ad, 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/2013/7/24/27Reported-and-tested-by: NJames Hogan <james@albanarts.com>
Reported-and-tested-by: NKamal Mostafa <kamal@canonical.com>
Reported-and-tested-by: NJörg Otte <jrg.otte@gmail.com>
Reported-and-tested-by: NSteven Newbury <steve@snewbury.org.uk>
Reported-by: NMartin Steigerwald <Martin@lichtvoll.de>
Reported-by: NKalle Valo <kvalo@adurom.com>
Tested-by: NJoerg Platte <jplatte@naasa.net>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

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=51231Tested-by: NAaron Lu <aaron.lu@intel.com>
Tested-by: NIgor Gnatenko <i.gnatenko.brain@gmail.com>
Tested-by: NYves-Alexis Perez <corsac@debian.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: NAaron Lu <aaron.lu@intel.com>
Acked-by: NMatthew Garrett <matthew.garrett@nebula.com>

Introduce helper function acpi_has_method() and use it in a number
of places to simplify code.

[rjw: Changelog]
Signed-off-by: NJiang Liu <jiang.liu@huawei.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Like on UL30VT, the ACPI video driver can't control backlight correctly on
Asus UL30A.  Vendor driver (asus-laptop) can work.  This patch is to
add "Asus UL30A" to ACPI video detect blacklist in order to use
asus-laptop for video control on the "Asus UL30A" rather than ACPI
video driver.
Signed-off-by: NBastian Triller <bastian.triller@gmail.com>
Cc: All <stable@vger.kernel.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

This patch updates the internal operations of acpi_device_set_id()
to setup acpi_device_pnp without using acpi_device.  There is no
functional change to acpi_device_set_id() in this patch.

acpi_pnp_type is added to acpi_device_pnp, so that PNPID type is
self-contained within acpi_device_pnp.  acpi_add_id(), acpi_bay_match(),
acpi_dock_match(), acpi_ibm_smbus_match() and acpi_is_video_device()
are changed to take acpi_handle as an argument, instead of acpi_device.
Signed-off-by: NToshi Kani <toshi.kani@hp.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>