Re: [PATCH] drm/i915/opregion: ignore firmware requests for backlight change

[Igor Gnatenko <i.gnatenko.brain@gmail.com>]

I've tested legacy boot. I have this bug.
On Fri, Jun 27, 2014 at 7:20 AM, Aaron Lu <aaron.lu@intel.com> wrote:
> On 06/25/2014 07:08 PM, Jani Nikula wrote:
>> On Tue, 24 Jun 2014, Aaron Lu <aaron.lu@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,
>
> Are you using legacy boot or UEFI boot?
> Possible to test the other case?
>
>>
>> One comment inline, otherwise
>
> Will add that in next revision.
>
>>
>> Acked-by: Jani Nikula <jani.nikula@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@gmail.com>
>>> Reported-and-tested-by: Anton Gubarkov <anton.gubarkov@gmail.com>
>>> Signed-off-by: Aaron Lu <aaron.lu@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