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ACPI / i915: ignore firmware requests for backlight change 

Some Thinkpad laptops' firmware will initiate a backlight level change
request through operation region on the events of AC plug/unplug, but
since we are not using firmware's interface to do the backlight setting
on these affected laptops, we do not want the firmware to use some
arbitrary value from its ASL variable to set the backlight level on
AC plug/unplug either.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=76491
Link: https://bugzilla.kernel.org/show_bug.cgi?id=77091
Reported-and-tested-by: Igor Gnatenko <i.gnatenko.brain@gmail.com>
Reported-and-tested-by: Anton Gubarkov <anton.gubarkov@gmail.com>
Signed-off-by: Aaron Lu <aaron.lu@intel.com>
Acked-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Aaron Lu 2014-07-07 15:43:51 +08:00 committed by Rafael J. Wysocki
parent cd3de83f14
commit 0b9f7d93ca
3 changed files with 13 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
drivers/acpi/video.c
View File

@ -241,13 +241,14 @@ static bool acpi_video_use_native_backlight(void)
return use_native_backlight_dmi;
}
static bool acpi_video_verify_backlight_support(void)
bool acpi_video_verify_backlight_support(void)
{
if (acpi_osi_is_win8() && acpi_video_use_native_backlight() &&
backlight_device_registered(BACKLIGHT_RAW))
return false;
return acpi_video_backlight_support();
}
EXPORT_SYMBOL_GPL(acpi_video_verify_backlight_support);
/* backlight device sysfs support */
static int acpi_video_get_brightness(struct backlight_device *bd)

9
drivers/gpu/drm/i915/intel_opregion.c
View File

@ -403,6 +403,15 @@ static u32 asle_set_backlight(struct drm_device *dev, u32 bclp)
DRM_DEBUG_DRIVER("bclp = 0x%08x\n", bclp);
/*
* If the acpi_video interface is not supposed to be used, don't
* bother processing backlight level change requests from firmware.
*/
if (!acpi_video_verify_backlight_support()) {
DRM_DEBUG_KMS("opregion backlight request ignored\n");
return 0;
}
if (!(bclp & ASLE_BCLP_VALID))
return ASLC_BACKLIGHT_FAILED;

2
include/acpi/video.h
View File

@ -22,6 +22,7 @@ extern void acpi_video_unregister(void);
extern void acpi_video_unregister_backlight(void);
extern int acpi_video_get_edid(struct acpi_device *device, int type,
int device_id, void **edid);
extern bool acpi_video_verify_backlight_support(void);
#else
static inline int acpi_video_register(void) { return 0; }
static inline void acpi_video_unregister(void) { return; }
@ -31,6 +32,7 @@ static inline int acpi_video_get_edid(struct acpi_device *device, int type,
{
return -ENODEV;
}
static inline bool acpi_video_verify_backlight_support(void) { return false; }
#endif
#endif