The ACPI video module provides two functionalities: backlight control and backlight hotkey event delivery. It is possible the backlight control interface is broken while the system still needs its event delivery, so it's worth to seperate the two interfaces clearly.
This patchset has two patches, the first is to sepeate the two interfaces in the ACPI video module and the second one solves some Win8 backlight control problems by removing ACPI video's backlight interface while still keeping its event delivery functionality. Due to some systems whose firmware claims win8 compatible have problems with i915's backlight control interface, a module param is introduced to give user a chance to select if they want to remove ACPI video's backlight control interface. The param is set to false by default.
Aaron Lu (2): ACPI / video: seperate backlight control and event interface ACPI / video / i915: Remove ACPI backlight if firmware expects Windows 8
drivers/acpi/internal.h | 2 + drivers/acpi/video.c | 473 +++++++++++++++++++++++----------------- drivers/acpi/video_detect.c | 15 +- drivers/gpu/drm/i915/i915_dma.c | 2 +- drivers/gpu/drm/i915/i915_drv.c | 5 + drivers/gpu/drm/i915/i915_drv.h | 1 + include/acpi/video.h | 11 +- include/linux/acpi.h | 1 + 8 files changed, 310 insertions(+), 200 deletions(-)