diff options
| author | Aaron Lu <aaron.lu@intel.com> | 2013-10-11 17:27:45 +0400 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2013-10-16 03:16:04 +0400 |
| commit | fbc9fe1b4f222a7c575e3bd8e9defe59c6190a04 (patch) | |
| tree | c76ebdac257ec5c565bad1d7f9fc865114093aad /drivers/acpi/internal.h | |
| parent | 67b662e189f469c6d373f81d76b0ef0495940e99 (diff) | |
| download | linux-fbc9fe1b4f222a7c575e3bd8e9defe59c6190a04.tar.xz | |
ACPI / video: Do not register backlight if win8 and native interface exists
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: Aaron Lu <aaron.lu@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/acpi/internal.h')
| -rw-r--r-- | drivers/acpi/internal.h | 4 |
1 files changed, 1 insertions, 3 deletions
diff --git a/drivers/acpi/internal.h b/drivers/acpi/internal.h index 20f423337e1f..e9304dc7ebfa 100644 --- a/drivers/acpi/internal.h +++ b/drivers/acpi/internal.h @@ -169,9 +169,7 @@ int acpi_create_platform_device(struct acpi_device *adev, Video -------------------------------------------------------------------------- */ #if defined(CONFIG_ACPI_VIDEO) || defined(CONFIG_ACPI_VIDEO_MODULE) -bool acpi_video_backlight_quirks(void); -#else -static inline bool acpi_video_backlight_quirks(void) { return false; } +bool acpi_osi_is_win8(void); #endif #endif /* _ACPI_INTERNAL_H_ */ |