[Intel-gfx] i915 issues with 4.6

[Pierre-Louis Bossart]

On 5/18/16 3:53 PM, Pierre-Louis Bossart wrote:
> On 5/18/16 2:08 AM, Ville Syrjälä wrote:
>> On Tue, May 17, 2016 at 07:09:58PM -0500, Pierre-Louis Bossart wrote:
>>>
>>>
>>> On 05/17/2016 01:16 PM, Ville Syrjälä wrote:
>>>> On Tue, May 17, 2016 at 01:00:13PM -0500, Pierre-Louis Bossart wrote:
>>>>> Hi,
>>>>> I was porting the HDMI audio patch to 4.6 as a service to several
>>>>> folks
>>>>> who need them before we finally upstream the reworked code, and I
>>>>> notice
>>>>> that the UI would freeze within 2s to 5mn, with all sorts of GPU hangs
>>>>> and issues reported in dmesg and /sys/calls/drm/card0/error
>>>>> Things work fine with the latest drm-intel-nightly branch from last
>>>>> night
>>>>> Known issue or should I file a bug?
>>>> One GPU hang generally looks like any other from the symptom POV.
>>>> Without the error state it's pretty much impossible to speculate.
>>>> Just filing a new bug is usually the best policy.
>>>>
>>>> If it's indeed a kernel regression a bisect would also be helpful.
>>>> Or in this case perhaps a reverse bisect since you say nightly is
>>>> fine, so we might want to know what fixed it.
>>>
>>> bug filed at https://bugs.freedesktop.org/show_bug.cgi?id=95467
>>>
>>> V4.5 works fine
>>> v4.6 is broken in less than 20s when moving windows around (can still
>>> get to virtual console)
>>> drm-intel-nightly works fine
>>>
>>> git bisect says this commit fixes the issue:
>>>
>>> commit a5e485a95c9c4cdd93b4c6dc53eee3bd1e50de11
>>> Author: Ville Syrjälä <ville.syrjala at linux.intel.com
>>> <mailto:ville.syrjala at linux.intel.com>>
>>> Date:   Wed Apr 13 21:19:51 2016 +0300
>>>
>>>      drm/i915: Clear VLV_IER around irq processing
>>
>> Argh. So somehow the broken commit [1] got into 4.6. We'll need to get
>> it reverted.
>>
>> [1] 9dbaab56ac09 ("drm/i915: Exit cherryview_irq_handler() after one
>> pass")
>
> git revert 9dbaab56ac09 works fine on my Ara X5 Plus.

I see patches being submitted to 4.6 stable now, is anyone on the 
graphics team planning to send a patch for this one or should I go ahead 
and do it?