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

[Deucher, Alexander]

> -----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.

Alex

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