Commit 0b9f7d93 authored by Aaron Lu's avatar Aaron Lu Committed by Rafael J. Wysocki
Browse files

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: default avatarIgor Gnatenko <i.gnatenko.brain@gmail.com>
Reported-and-tested-by: default avatarAnton Gubarkov <anton.gubarkov@gmail.com>
Signed-off-by: default avatarAaron Lu <aaron.lu@intel.com>
Acked-by: default avatarJani Nikula <jani.nikula@intel.com>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent cd3de83f

drivers/acpi/video.c

+2 −1
Original line number Diff line number Diff line
@@ -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)

drivers/gpu/drm/i915/intel_opregion.c

+9 −0
Original line number Diff line number Diff line
@@ -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;

include/acpi/video.h

+2 −0
Original line number Diff line number Diff line
@@ -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

CRA Git | Maintained and supported by SUSTech CRA and CCSE