[Intel-gfx] [PATCH] drm/i915/opregion: ignore firmware requests for backlight change

[Igor Gnatenko]

On Fri, 2014-06-27 at 11:20 +0800, Aaron Lu wrote: 
> On 06/25/2014 07:08 PM, Jani Nikula wrote:
> > On Tue, 24 Jun 2014, Aaron Lu <aaron.lu at intel.com> wrote:
> >> 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.
> > 
> > I'm curious whether this happens with EFI boot, or only with legacy.
> 
> Igor, Anton,
Hi,
> Are you using legacy boot or UEFI boot?
I'm using UEFI. 
> Possible to test the other case?
yes, I'll test it with legacy in 10 mins. 
> 
> > 
> > One comment inline, otherwise
> 
> Will add that in next revision.
> 
> > 
> > Acked-by: Jani Nikula <jani.nikula at intel.com>
> 
> Thanks for the review!
> 
> -Aaron
> 
> > 
> > for merging through the ACPI tree, as the change is more likely to
> > conflict there.
> > 
> >> Buglink: https://bugzilla.kernel.org/show_bug.cgi?id=76491
> >> Buglink: https://bugzilla.kernel.org/show_bug.cgi?id=77091
> >> Reported-and-tested-by: Igor Gnatenko <i.gnatenko.brain at gmail.com>
> >> Reported-and-tested-by: Anton Gubarkov <anton.gubarkov at gmail.com>
> >> Signed-off-by: Aaron Lu <aaron.lu at intel.com>
> >> ---
> >>  drivers/acpi/video.c                  | 3 ++-
> >>  drivers/gpu/drm/i915/intel_opregion.c | 7 +++++++
> >>  include/acpi/video.h                  | 2 ++
> >>  3 files changed, 11 insertions(+), 1 deletion(-)
> >>
> >> diff --git a/drivers/acpi/video.c b/drivers/acpi/video.c
> >> index fb9ffe9adc64..cf99d6d2d491 100644
> >> --- a/drivers/acpi/video.c
> >> +++ b/drivers/acpi/video.c
> >> @@ -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(acpi_video_verify_backlight_support);
> >>  
> >>  /* backlight device sysfs support */
> >>  static int acpi_video_get_brightness(struct backlight_device *bd)
> >> diff --git a/drivers/gpu/drm/i915/intel_opregion.c b/drivers/gpu/drm/i915/intel_opregion.c
> >> index 2e2c71fcc9ed..02943d93e88e 100644
> >> --- a/drivers/gpu/drm/i915/intel_opregion.c
> >> +++ b/drivers/gpu/drm/i915/intel_opregion.c
> >> @@ -403,6 +403,13 @@ 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())
> >> +		return 0;
> > 
> > I'd appreciate a DRM_DEBUG_KMS here about what happened. We're bound to
> > wonder about that staring at some dmesg later on!
> > 
> >> +
> >>  	if (!(bclp & ASLE_BCLP_VALID))
> >>  		return ASLC_BACKLIGHT_FAILED;
> >>  
> >> diff --git a/include/acpi/video.h b/include/acpi/video.h
> >> index ea4c7bbded4d..92f8c4bffefb 100644
> >> --- a/include/acpi/video.h
> >> +++ b/include/acpi/video.h
> >> @@ -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 bool acpi_video_verify_backlight_support() { return false; }
> >>  #endif
> >>  
> >>  #endif
> >> -- 
> >> 1.9.3
> >>
> > 
> 


-- 
-Igor Gnatenko
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