RE: [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@xxxxxxxxxxxxx]
> Sent: Thursday, January 08, 2015 4:58 PM
> To: Deucher, Alexander
> Cc: stable@xxxxxxxxxxxxxxx; 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@xxxxxxxxxxxxx]
> >> Sent: Thursday, January 08, 2015 11:26 AM
> >> To: Deucher, Alexander
> >> Cc: stable@xxxxxxxxxxxxxxx; 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@xxxxxxxxxxxxx]
> >>>> Sent: Wednesday, January 07, 2015 5:51 PM
> >>>> To: Deucher, Alexander
> >>>> Cc: stable@xxxxxxxxxxxxxxx; 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@xxxxxxx>
> >>>> 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.

Thanks,

Alex

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