[Regression][v3.17][3.18][3.19-rc3] drm/radeon: re-enable dpm by default on BTC

[Joseph Salisbury]

On 01/08/2015 05:00 PM, Deucher, Alexander wrote:
>> -----Original Message-----
>> From: Joseph Salisbury [mailto:joseph.salisbury at canonical.com]
>> Sent: Thursday, January 08, 2015 4:58 PM
>> To: Deucher, Alexander
>> Cc: stable at vger.kernel.org; LKML; Koenig, Christian; David Airlie; dri-devel
>> Subject: Re: [Regression][v3.17][3.18][3.19-rc3] drm/radeon: re-enable dpm
>> by default on BTC
>>
>> On 01/08/2015 12:48 PM, Deucher, Alexander wrote:
>>>> -----Original Message-----
>>>> From: Joseph Salisbury [mailto:joseph.salisbury at canonical.com]
>>>> Sent: Thursday, January 08, 2015 11:26 AM
>>>> To: Deucher, Alexander
>>>> Cc: stable at vger.kernel.org; LKML; Koenig, Christian; David Airlie; dri-devel
>>>> Subject: Re: [Regression][v3.17][3.18][3.19-rc3] drm/radeon: re-enable
>> dpm
>>>> by default on BTC
>>>>
>>>> On 01/07/2015 09:51 PM, Deucher, Alexander wrote:
>>>>>> -----Original Message-----
>>>>>> From: Joseph Salisbury [mailto:joseph.salisbury at canonical.com]
>>>>>> Sent: Wednesday, January 07, 2015 5:51 PM
>>>>>> To: Deucher, Alexander
>>>>>> Cc: stable at vger.kernel.org; LKML; Koenig, Christian; David Airlie; dri-
>> devel
>>>>>> Subject: [Regression][v3.17][3.18][3.19-rc3] drm/radeon: re-enable
>> dpm
>>>> by
>>>>>> default on BTC
>>>>>>
>>>>>> Hi Alexander,
>>>>>>
>>>>>> A kernel bug report was opened against Ubuntu [0].  After a kernel
>>>>>> bisect, it was found that reverting the following commit resolved this
>> bug:
>>>>>> commit c08abf11900e19b14dd3a0cc3d105bd74519cd18
>>>>>> Author: Alex Deucher <alexander.deucher at amd.com>
>>>>>> Date:   Mon Jul 14 12:01:40 2014 -0400
>>>>>>
>>>>>>     drm/radeon: re-enable dpm by default on BTC
>>>>>>
>>>>>> The regression was introduced as of v3.17-rc1 and still exists in
>>>>>> current mainline.  It has also made it's way into the stable releases.
>>>>>>
>>>>>> I was hoping to get your feedback, since you are the patch author.  Do
>>>>>> you think gathering any additional data will help diagnose this issue,
>>>>>> or would it be best to submit a revert request?
>>>>>>
>>>>> Does revering b2dccf24e77 help?  I'd hate to revert this patch because it
>>>> disables power management for a whole family of chips.  If it doesn't help
>> I'd
>>>> prefer to just add a quirk to disable it for the specific problematic board.
>>>> Commit b2dccf24e77 was added to mainline as of v3.18-rc1 and was not
>>>> cc'd to stable.  We are also seeing this issue in the 3.13.y stable
>>>> kernel, which does not have commit b2dccf24e77 applied.  However, we
>> can
>>>> test reverting it in mainline?
>>> Nope.  Won't make a difference.  The attached patch adds a quirk list for
>> dpm which will fix the issue for the affected boards.
>>> Alex
>> Thanks again for the patch, Alex.  The bug reporter has tested a 3.16
>> kernel with the patch and says it fixes the bug.
> I'll queue it up for 3.19-fixes and cc stable.
Great.  Thanks, again!


> Thanks,
>
> Alex
>
>>
>>>>> Alex
>>>>>
>>>>>> Thanks,
>>>>>>
>>>>>> Joe
>>>>>>
>>>>>> [0] http://pad.lv/1386534