If the _BCL package ordering is descending, the first level
(br->levels[2]) is likely to be 0, and if the number of levels
matches the number of steps, we might confuse a returned level to
mean the index.

For example:

  current_level = max_level = 100
  test_level = 0
  returned level = 100

In this case 100 means the level, not the index, and _BCM failed.
Still, if the _BCL package ordering is descending, the index of
level 0 is also 100, so we assume _BQC is indexed, when it's not.

This causes all _BQC calls to return bogus values causing weird
behavior from the user's perspective.  For example:

xbacklight -set 10; xbacklight -set 20;

would flash to 90% and then slowly down to the desired level (20).

The solution is simple; test anything other than the first level
(e.g. 1).

[rjw: Changelog]
Signed-off-by: NFelipe Contreras <felipe.contreras@gmail.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>

The BIOS of FUjitsu E753 reports an incorrect initial backlight value
for WIN8 compatible OS, causing backlight to be dark during startup.
This change causes the incorrect initial value from BIOS to be ignored.

References: https://bugzilla.kernel.org/show_bug.cgi?id=60161Reported-and-tested-by: NJan Hinnerk Stosch <janhinnerk.stosch@gmail.com>
Signed-off-by: NLan Tianyu <tianyu.lan@intel.com>
Cc: 3.7+ <stable@vger.kernel.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Starting from win8, MS backlight control driver will set bit 2 of the
parameter of control method _DOS, to inform firmware it should not
perform any automatic brightness changes. This mostly affects hotkey
notification deliver - if we do not set this bit, on hotkey press,
firmware may choose to adjust brightness level instead of sending out
notification and doing nothing.

So this patch sets bit 2 when calling _DOS so that GUIs can show the
notification window on hotkey press.  This behavior change is only
necessary for win8 systems.

The MS document on win8 backlight control is here:
http://msdn.microsoft.com/en-US/library/windows/hardware/jj159305

References: https://bugzilla.kernel.org/show_bug.cgi?id=52951
References: https://bugzilla.kernel.org/show_bug.cgi?id=56711Reported-by: NMicael Dias <kam1kaz3@gmail.com>
Reported-by: NDan Garton <dan.garton@gmail.com>
Reported-by: NBob Ziuchkovski <bob.ziuchkovski@gmail.com>
Signed-off-by: NAaron Lu <aaron.lu@intel.com>
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>

We have to call acpi_video_init_brightness() even if we're not going
to initialise the backlight - Thinkpads seem to use this as the
trigger for enabling ACPI notifications rather than handling it in
firmware.

[rjw: Drop the brightness object created by
 acpi_video_init_brightness() if we are not going to use it.]
Signed-off-by: NMatthew Garrett <matthew.garrett@nebula.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

ACPI drivers must not be bound to device objects having scan handlers
attatched to them, so make acpi_device_probe() fail with -EINVAL if the
device object being probed has an ACPI scan handler.

After this change the analogous check introduced into the ACPI video
driver by commit 8c9b7a7b (ACPI / video: Do not bind to device objects
with a scan handler) is not necessary any more and may be dropped, so
drop it.
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: NTony Luck <tony.luck@gmail.com>
Acked-by: NToshi Kani <toshi.kani@hp.com>

With the introduction of ACPI scan handlers, ACPI device objects
with an ACPI scan handler attached to them must not be bound to
by ACPI drivers any more.  Unfortunately, however, the ACPI video
driver attempts to do just that if there is a _ROM ACPI control
method defined under a device object with an ACPI scan handler.

Prevent that from happening by making the video driver's "add"
routine check if the device object already has an ACPI scan handler
attached to it and return an error code in that case.

That is not sufficient, though, because acpi_bus_driver_init() would
then clear the device object's driver_data that may be set by its
scan handler, so for the fix to work acpi_bus_driver_init() has to be
modified to leave driver_data as is on errors.

References: https://bugzilla.kernel.org/show_bug.cgi?id=58091Bisected-and-tested-by: NDmitry S. Demin <dmitryy.demin@gmail.com>
Reported-and-tested-by: NJason Cassell <bluesloth600@gmail.com>
Tracked-down-by: NAaron Lu <aaron.lu@intel.com>
Cc: 3.9+ <stable@kernel.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: NAaron Lu <aaron.lu@intel.com>

This patch addresses kernel bug 56661. BIOS reports an incorrect
backlight value, causing the driver to switch off the backlight
completely during startup. This patch ignores the incorrect value from
BIOS.

References: https://bugzilla.kernel.org/show_bug.cgi?id=56661Signed-off-by: NAsh Willis <ashwillis@programmer.net>
Cc: All <stable@vger.kernel.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

On HP m4 lapops, BIOS reports minimum backlight on boot and
causes backlight to dim completely. This ignores the initial backlight
values and set to max brightness.

References: https://bugs.launchpad.net/bugs/1184501
Cc: All <stable@vger.kernel.org>
Signed-off-by: NAlex Hung <alex.hung@canonical.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

On HP 1000 lapops, BIOS reports minimum backlight on boot and
causes backlight to dim completely. This ignores the initial backlight
values and set to max brightness.

References:: https://bugs.launchpad.net/bugs/1167760Signed-off-by: NAlex Hung <alex.hung@canonical.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

acpi_video_bus_get_devices() may fail due to some video output device
doesn't have the _ADR method, and in this case, the error processing
is to simply free the video structure in acpi_video_bus_add(), while
leaving those already registered video output devices in the wild,
which means for some video output device, we have already registered
a backlight interface and installed a notification handler for it.
So it can happen when user is using this system, on hotkey pressing,
the notification handler will send a keycode through a non-existing
input device, causing kernel freeze.

To solve this problem, free all those already registered video output
devices once something goes wrong in acpi_video_bus_get_devices(), so
that no wild backlight interfaces and notification handlers exist.

References: https://bugzilla.kernel.org/show_bug.cgi?id=51731
Reported-and-tested-by: <i-tek@web.de>
Signed-off-by: NAaron Lu <aaron.lu@intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Currently we decide if the _BQC is using index by first setting the
level to maximum, and then check if _BQC returned maximum; if not, we
say it is using index.

This is not true for some buggy systems, where the _BQC method will
always return a constant value(e.g. 0 or 100 for the two broken system)
and thus break the current logic. So this patch tries to enhance the
quirk detect logic for _BQC: we do this by picking a test_level, it can
be the maximum level or the mininum one based on some condition. And we
don't make the assumption that if _BQC returned a value that is not what
we just set, it must be using an index. Instead, we will compare the
value returned from _BQC and if it doesn't match, see if the returned
value is an index. And if still no, clear the capability of _BQC.

References: https://bugzilla.kernel.org/show_bug.cgi?id=42861
References: https://bugzilla.kernel.org/show_bug.cgi?id=56011Reported-and-tested-by: NArtem Savkov <artem.savkov@gmail.com>
Reported-by: NLuis Medinas <lmedinas@gmail.com>
Reported-by: NCheppes <cheppes@mailinator.com>
Signed-off-by: NAaron Lu <aaron.lu@intel.com>
Acked-by: NZhang Rui <rui.zhang@intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

The value initially read via _BQC also needs to be offset by 2 to
compensate for the first 2 special items in _BCL. Introduce a helper
function that does the BQC-value-to-level conversion in order to not
needlessly duplicate code.
Signed-off-by: NDanny Baumann <dannybaumann@web.de>
Reviewed-by: NAaron Lu <aaron.lu@intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Make code paths a little easier to follow, and don't needlessly continue
list iteration.
Signed-off-by: NDanny Baumann <dannybaumann@web.de>
Reviewed-by: NAaron Lu <aaron.lu@intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

In particular, this fixes brightness control initialization for all
devices that return index values from _BQC and don't happen to have the
initial index set by the BIOS in their _BCL table. One example for that
is the Dell Inspiron 15R SE (model number 7520).

What happened for those devices is that acpi_init_brightness queried the
initial brightness by calling acpi_video_device_lcd_get_level_current.
This called _BQC, which returned e.g. 13. As _BQC_use_index isn't
determined at this point (and thus has its initial value of 0), the
index isn't converted into the actual level. As '13' isn't present in
the _BCL list, *level is later overwritten with brightness->curr, which
was initialized to max_level (100) before. Later in
acpi_init_brightness, level_old (with the value 100) is used as an index
into the _BCL table, which causes a value outside of the actual table to
be used as input into acpi_video_device_lcd_set_level(). Depending on
the (undefined) value of that location, this call will fail, causing the
brightness control for the device in question not to be enabled.

Fix that by returning the raw value returned by the _BQC call in the
initialization case.
Signed-off-by: NDanny Baumann <dannybaumann@web.de>
Reviewed-by: NAaron Lu <aaron.lu@intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

On a HP Pavilion dm4 laptop the BIOS sets minimum backlight on boot,
completely dimming the screen. Ignore this initial value for this
machine.
Signed-off-by: NGustavo Maciel Dias Vieira <gustavo@sagui.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

The second argument of ACPI driver .remove() operation is only used
by the ACPI processor driver and the value passed to that driver
through it is always available from the given struct acpi_device
object's removal_type field.  For this reason, the second ACPI driver
.remove() argument is in fact useless, so drop it.
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: NJiang Liu <jiang.liu@huawei.com>
Acked-by: NToshi Kani <toshi.kani@hp.com>
Acked-by: NYinghai Lu <yinghai@kernel.org>

ACPI_ERROR() already appends a newline, so there is no
need for the error messages to include one too.
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Or else the laptop will boot with a dimmed screen.

References: https://bugzilla.kernel.org/show_bug.cgi?id=51141Tested-by: NStefan Nagy <public@stefan-nagy.at>
Signed-off-by: NZhang Rui <rui.zhang@intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

There are systems where video module known to work fine regardless
of broken _DOD and ignoring returned value here doesn't cause
any issues later. This should fix brightness controls on some laptops.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=47861Signed-off-by: NIgor Murzov <e-mail@date.by>
Reviewed-by: NSergey V <sftp.mtuci@gmail.com>
Signed-off-by: NZhang Rui <rui.zhang@intel.com>

The standard video events may be overloaded for device specific
purposes. For example AMD ACPI interface overloads
ACPI_VIDEO_NOTIFY_PROBE (0x81) to signal AMD-specific events. In such
cases we don't want to send the keypress (KEY_SWITCHVIDEOMODE) to the
userspace because the user did not press the mode switch key (the
spurious keypress confuses the DE which usually changes the
display configuration and messes up a dual-screen setup).
This patch gives the handlers the chance to examine the event and
block the keypress if the event is device specific.
v2: refactor as suggested by Zhang Rui <rui.zhang@intel.com>
Signed-off-by: NLuca Tettamanti <kronos.it@gmail.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

This fixes a regression in 3.4-rc1 caused by commit
ea9f8856
(ACPI video: Harden video bus adding.)

Some platforms don't have _DOS control method, but the ACPI
backlight still works.
We should not invoke _DOS for these platforms.

https://bugzilla.kernel.org/show_bug.cgi?id=43168

Cc: Igor Murzov <intergalactic.anonymous@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: NZhang Rui <rui.zhang@intel.com>
Signed-off-by: NLen Brown <len.brown@intel.com>

We can't use "input" anymore after calling input_unregister_device().
The call to input_free_device() is a double free.  The normal way to
deal with this is to make input_register_device() the last function
called in the function.
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Acked-by: NDmitry Torokhov <dtor@mail.ru>
Signed-off-by: NLen Brown <len.brown@intel.com>

Stop it poking at random registers on the i740 cards that may be out there
still.

As per Matthew's feedback remove the conditional checks and never enable the
opregion handling unless an appropriate driver has been loaded.
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NLen Brown <len.brown@intel.com>

Signed-off-by: NAlan Cox <alan@linux.intel.com>
Acked-by: NMatthew Garrett <mjg@redhat.com>
Signed-off-by: NLen Brown <len.brown@intel.com>

Quoth Dmitry Torokhov:
In addition to bus notifier we do install device notifier explicitly
so it might fire up early. The easiest fox would be to move
acpi_video_bus_start_devices() after input_allocate_device() but
before input_register_device() - unregistered input devices can handle
input_event() calls just fine.

May fix crashes reported in:
https://bugzilla.kernel.org/show_bug.cgi?id=40672Signed-off-by: NIgor Murzov <e-mail@date.by>
Signed-off-by: NLen Brown <len.brown@intel.com>

It is always better to check return values, so add some new checks and
correct existing ones.

v2: Be consistent and don't mix errors from -E* and AE_* namespaces.
Signed-off-by: NIgor Murzov <e-mail@date.by>
Signed-off-by: NLen Brown <len.brown@intel.com>

module_param(bool) used to counter-intuitively take an int.  In
fddd5201 (mid-2009) we allowed bool or int/unsigned int using a messy
trick.

It's time to remove the int/unsigned int option.  For this version
it'll simply give a warning, but it'll break next kernel version.
Acked-by: NMauro Carvalho Chehab <mchehab@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

Structs battery_file, acpi_dock_ops, file_operations,
thermal_cooling_device_ops, thermal_zone_device_ops, kernel_param_ops
are not changed in runtime.  It is safe to make them const.
register_hotplug_dock_device() was altered to take const "ops" argument
to respect acpi_dock_ops' const notion.
Signed-off-by: NVasiliy Kulikov <segoon@openwall.com>
Acked-by: NJeff Garzik <jgarzik@redhat.com>
Signed-off-by: NLen Brown <len.brown@intel.com>

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: NMatthew Garrett <mjg@redhat.com>
Tested-by: NAdam Jackson <ajax@redhat.com>
Signed-off-by: NKeith Packard <keithp@keithp.com>

- kenrel -> kernel
- whetehr -> whether
- ttt -> tt
- sss -> ss
Signed-off-by: NJustin P. Mattock <justinmattock@gmail.com>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>

Fixes generated by 'codespell' and manually reviewed.
Signed-off-by: NLucas De Marchi <lucas.demarchi@profusion.mobi>

The acpi video driver attempts to explicitly create a sysfs link between
the acpi device and the associated PCI device. However, we're now also
doing this from the backlight core, which means that we get a backtrace
caused by a duplicate file. Remove the code and leave it up to the
backlight core.
Reported-by: NJeff Chua <jeff.chua.linux@gmail.com>
Signed-off-by: NMatthew Garrett <mjg@redhat.com>
Acked-by: NRafael J. Wysocki <rjw@sisk.pl>
Tested-by: NAlessandro Suardi <alessandro.suardi@gmail.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Dual-GPU machines may provide more than one ACPI backlight interface.  Tie
the backlight device to the GPU in order to allow userspace to identify
the correct interface.
Signed-off-by: NMatthew Garrett <mjg@redhat.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: David Airlie <airlied@linux.ie>
Cc: Alex Deucher <alexdeucher@gmail.com>
Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Zhang Rui <rui.zhang@intel.com>
Cc: Len Brown <lenb@kernel.org>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Tested-by: NSedat Dilek <sedat.dilek@googlemail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

There may be multiple ways of controlling the backlight on a given
machine.  Allow drivers to expose the type of interface they are
providing, making it possible for userspace to make appropriate policy
decisions.
Signed-off-by: NMatthew Garrett <mjg@redhat.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: David Airlie <airlied@linux.ie>
Cc: Alex Deucher <alexdeucher@gmail.com>
Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Zhang Rui <rui.zhang@intel.com>
Cc: Len Brown <lenb@kernel.org>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Introduce module parameter video.use_bios_initial_backlight.

Some BIOSes claim they use the minimum backlight at boot,
and this may bring dimming screen after boot.
https://bugzilla.kernel.org/show_bug.cgi?id=21212

use video.use_bios_initl_backlight=0 to use
the maximum backlight level after boot.
Signed-off-by: NZhang Rui <rui.zhang@intel.com>
Signed-off-by: NLen Brown <len.brown@intel.com>

cap._DDC is defined but never used.
Check this flag now and don't try to get EDID for video output devices with this flag cleared.
Signed-off-by: NZhang Rui <rui.zhang@intel.com>
Signed-off-by: NLen Brown <len.brown@intel.com>

Remove the ACPI video output switching control as it never works.

With the patch applied,
ACPI video driver still catches the video output notification,
but it does nothing but raises the notification to userspace.
Signed-off-by: NZhang Rui <rui.zhang@intel.com>
Signed-off-by: NLen Brown <len.brown@intel.com>

backlight_device_register has been expecting a const "ops" argument, and using
it as such, since 9905a43b. Let's make the
remaining backlight_ops instances const.

Inspired by hunks of the grsecurity patch, updated for newer kernels.
Signed-off-by: NLionel Debroux <lionel_debroux@yahoo.fr>
Acked-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>