[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: 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

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

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