Glitch in newer drm-next/drm-radeon-testing

[Alex Deucher]

2010/6/4 Marius Gröger <marius.groeger at googlemail.com>:
> Hi All,
>
> Michel Dänzer schrieb:
>> On Mit, 2010-06-02 at 08:07 +0200, Marius Gröger wrote:
>>> Hello All,
>>>
>>> I'm trying the top-of-trunk drm-2.6 trees (both drm-next and
>>> drm-radeon-testing) with my Radeon HD 3200 GPU over HDMI. The primary
>>> application is mythtv which uses DRM syncing for the frame
>>> syncronisation. Now, with the exact same userland software I noticed the
>>> introduction of sync gliches in the May-timeframe. The
>>> drm-radeon-testing on May 9 was still ok, but both drm-next and
>>> drm-radeon-testing at the end of May showed that glitch: every couple of
>>> seconds there's a very visual hickup, especially in scroll texts.
>>>
>>> Apologies for such an unspecific description, and for what almost seems
>>> like a support request for MythTV. I wouldn't post here if I were not
>>> 100% sure it must be related with the recent drm changes.
>>
>> Note that the DRM APIs are intended for use by userspace components of
>> graphics drivers / API libraries, not applications directly. MythTV
>> shouldn't use the DRM directly for synchronization but rather use GLX
>> synchronization APIs.
>
> What about that new dri2 vsync stuff which was mentioned related to [Bug
> 28383]? Could the changes done for that in any way alter the timing? BTW
> I measured the glitches I'm experiencing and the appear to be to happen
> in intervals of 10 seconds. Again, all I'm changing is the kernel, and
> even the kernel config is the same. I'd be most grateful for any
> clues/hints/tips I could follow to resolve this regression.
>
>> If you have dynamic PM enabled, does disabling that help?
>
> I checked again and there's method=profile and profile=default. Afaict
> this is not using dynpm, right?
>

Correct.

Alex