No backlight since linux-4.2.4 - drivers/gpu/drm/radeon/atombios_encoders.c

[Michel Dänzer]

Michael, please keep the Cc: list intact.


On 26.10.2015 19:46, Michael Burian wrote:
> On 10/26/15 10:32, Michel Dänzer wrote:
>> On 25.10.2015 04:25, Michael Burian wrote:
>>>
>>> # first bad commit: [5a633828b4b2bef343826afcb0a70770c4911c55] drm/radeon: Restore LCD backlight level on resume (>= R5xx)
>>>
>>> Workaround 2:
>>>
>>> reverting this single commit 5a633828b4b2bef343826afcb0a70770c4911c55 fixes the problem in linux-stable[0]
>>> as well as mainline[1] 4.3.0-rc6-00277-g01815536
>>
>> Please provide the dmesg output from running with the attached debugging
>> patch.
>>
> 
> [0] contains dmesg output with your patch applied (which fixes the backlight issue)

This is very surprising: The patch just adds some debugging output, it's
not supposed to have any functional effect. Also, I don't see any of the
debugging output added by the patch in
dmesg-4.3.0-rc7-00003-g85051e2-dirty-2015-10-26-11-00-41-radeon-bl-debug.

Are you sure that my patch was actually applied to the radeon driver
when generating that file? Did you update the initrd with the patched
radeon.ko?


> [1] contains dmesg output without your patch for comparison (resulting in a permanent black screen as before in rc6)
> 
> 
> [0]
> dmesg-4.3.0-rc7-00003-g85051e2-dirty-2015-10-26-11-00-41-radeon-bl-debug
> 
> [1]
> dmesg-4.3.0-rc7-00003-g85051e2-2015-10-26-11-22-09
> 
> 




-- 
Earthling Michel Dänzer               |               http://www.amd.com
Libre software enthusiast             |             Mesa and X developer