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

[Marius Gröger]

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?

Marius