kernel/drivers/acpi/video.c, branch linux-3.11.y

ACPI / video: Quirk initial backlight level 0

2013-11-29T18:42:16Z

commit 2c62333a408f5badd2d2ffd7177f95deeccc5ca4 upstream. Some firmware doesn't initialize initial backlight level to a proper value and _BQC will return 0 on first time evaluation. We used to be able to detect such incorrect value with our code logic, as value 0 normally isn't a valid value in _BCL. But with the introduction of Win8, firmware begins to fill _BCL with values from 0 to 100, now 0 becomes a valid value but that value will make user's screen black. This patch test initial _BQC for value 0, if such a value is returned, do not use it. References: https://bugzilla.kernel.org/show_bug.cgi?id=64031 References: https://bugzilla.kernel.org/show_bug.cgi?id=61231 References: https://bugzilla.kernel.org/show_bug.cgi?id=63111 Reported-by: Qingshuai Tian Tested-by: Aaron Lu # on "Idealpad u330p" Reported-and-tested-by: # on "Acer Aspire V5-573G" Reported-and-tested-by: Kirill Tkhai # on "HP 250 G1" Signed-off-by: Aaron Lu Signed-off-by: Rafael J. Wysocki Signed-off-by: Greg Kroah-Hartman

Revert "ACPI / video: Always call acpi_video_init_brightness() on init"

2013-08-22T21:39:02Z

Revert commit c04c697 (ACPI / video: Always call acpi_video_init_brightness() on init), because it breaks eDP backlight at 1920x1080 on Acer Aspire S3 for Trevor Bortins. References: https://bugs.freedesktop.org/show_bug.cgi?id=68355 Reported-and-bisected-by: Trevor Bortins Signed-off-by: Rafael J. Wysocki

ACPI / video: improve quirk check in acpi_video_bqc_quirk()

2013-08-04T21:45:39Z

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: Felipe Contreras Signed-off-by: Rafael J. Wysocki

Revert "ACPI / video / i915: No ACPI backlight if firmware expects Windows 8"

2013-07-26T12:59:20Z

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 Reported-and-tested-by: Kamal Mostafa Reported-and-tested-by: Jörg Otte Reported-and-tested-by: Steven Newbury Reported-by: Martin Steigerwald Reported-by: Kalle Valo Tested-by: Joerg Platte Signed-off-by: Rafael J. Wysocki

Merge tag 'acpi-video-3.11' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

2013-07-21T17:11:04Z

Pull ACPI video support fixes from Rafael Wysocki: "I'm sending a separate pull request for this as it may be somewhat controversial. The breakage addressed here is not really new and the fixes may not satisfy all users of the affected systems, but we've had so much back and forth dance in this area over the last several weeks that I think it's time to actually make some progress. The source of the problem is that about a year ago we started to tell BIOSes that we're compatible with Windows 8, which we really need to do, because some systems shipping with Windows 8 are tested with it and nothing else, so if we tell their BIOSes that we aren't compatible with Windows 8, we expose our users to untested BIOS/AML code paths. However, as it turns out, some Windows 8-specific AML code paths are not tested either, because Windows 8 actually doesn't use the ACPI methods containing them, so if we declare Windows 8 compatibility and attempt to use those ACPI methods, things break. That occurs mostly in the backlight support area where in particular the _BCM and _BQC methods are plain unusable on some systems if the OS declares Windows 8 compatibility. [ The additional twist is that they actually become usable if the OS says it is not compatible with Windows 8, but that may cause problems to show up elsewhere ] Investigation carried out by Matthew Garrett indicates that what Windows 8 does about backlight is to leave backlight control up to individual graphics drivers. At least there's evidence that it does that if the Intel graphics driver is used, so we've decided to follow Windows 8 in that respect and allow i915 to control backlight (Daniel likes that part). The first commit from Aaron Lu makes ACPICA export the variable from which we can infer whether or not the BIOS believes that we are compatible with Windows 8. The second commit from Matthew Garrett prepares the ACPI video driver by making it initialize the ACPI backlight even if it is not going to be used afterward (that is needed for backlight control to work on Thinkpads). The third commit implements the actual workaround making i915 take over backlight control if the firmware thinks it's dealing with Windows 8 and is based on the work of multiple developers, including Matthew Garrett, Chun-Yi Lee, Seth Forshee, and Aaron Lu. The final commit from Aaron Lu makes us follow Windows 8 by informing the firmware through the _DOS method that it should not carry out automatic brightness changes, so that brightness can be controlled by GUI. Hopefully, this approach will allow us to avoid using blacklists of systems that should not declare Windows 8 compatibility just to avoid backlight control problems in the future. - Change from Aaron Lu makes ACPICA export a variable which can be used by driver code to determine whether or not the BIOS believes that we are compatible with Windows 8. - Change from Matthew Garrett makes the ACPI video driver initialize the ACPI backlight even if it is not going to be used afterward (that is needed for backlight control to work on Thinkpads). - Fix from Rafael J Wysocki implements Windows 8 backlight support workaround making i915 take over bakclight control if the firmware thinks it's dealing with Windows 8. Based on the work of multiple developers including Matthew Garrett, Chun-Yi Lee, Seth Forshee, and Aaron Lu. - Fix from Aaron Lu makes the kernel follow Windows 8 by informing the firmware through the _DOS method that it should not carry out automatic brightness changes, so that brightness can be controlled by GUI" * tag 'acpi-video-3.11' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: ACPI / video: no automatic brightness changes by win8-compatible firmware ACPI / video / i915: No ACPI backlight if firmware expects Windows 8 ACPI / video: Always call acpi_video_init_brightness() on init ACPICA: expose OSI version

ACPI / video: ignore BIOS initial backlight value for Fujitsu E753

2013-07-18T19:43:41Z

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=60161 Reported-and-tested-by: Jan Hinnerk Stosch Signed-off-by: Lan Tianyu Cc: 3.7+ Signed-off-by: Rafael J. Wysocki

ACPI / video: no automatic brightness changes by win8-compatible firmware

2013-07-18T00:08:16Z

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=56711 Reported-by: Micael Dias Reported-by: Dan Garton Reported-by: Bob Ziuchkovski Signed-off-by: Aaron Lu Signed-off-by: Rafael J. Wysocki

ACPI / video / i915: No ACPI backlight if firmware expects Windows 8

2013-07-18T00:08:06Z

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 Tested-by: Igor Gnatenko Tested-by: Yves-Alexis Perez Signed-off-by: Rafael J. Wysocki Reviewed-by: Aaron Lu Acked-by: Matthew Garrett

ACPI / video: Always call acpi_video_init_brightness() on init

2013-07-17T23:31:47Z

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: Matthew Garrett Signed-off-by: Rafael J. Wysocki

ACPI / scan: Do not bind ACPI drivers to objects with scan handlers

2013-06-19T23:25:19Z

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 8c9b7a7 (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: Rafael J. Wysocki Tested-by: Tony Luck Acked-by: Toshi Kani