From 0b9f7d93ca6109048a4eb06332b666b6e29df4fe Mon Sep 17 00:00:00 2001 From: Aaron Lu Date: Mon, 7 Jul 2014 15:43:51 +0800 Subject: 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 Reported-and-tested-by: Anton Gubarkov Signed-off-by: Aaron Lu Acked-by: Jani Nikula Signed-off-by: Rafael J. Wysocki --- drivers/gpu/drm/i915/intel_opregion.c | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'drivers/gpu/drm/i915/intel_opregion.c') diff --git a/drivers/gpu/drm/i915/intel_opregion.c b/drivers/gpu/drm/i915/intel_opregion.c index 2e2c71fcc9ed..4f6b53998d79 100644 --- a/drivers/gpu/drm/i915/intel_opregion.c +++ b/drivers/gpu/drm/i915/intel_opregion.c @@ -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; -- cgit v1.2.3