xf86-video-intel refresh and DebugWait

creepytennis · n00b Joined: 03 Apr 2007 Posts: 37

Hi,

I've just upgraded from xf86-video-intel 2.8.1 to xf86-video-intel-2.9.1. The problem which appeared is quite strange. OpenGL apps run at a good framerate, but they refresh to the screen very erratically. For example glxgears will display a few frames smoothly, then 'jump' a number of frames. This happens at a regular rhythm of about half a second.

The only thing which fixes the issue is to add 'Option "DebugWait" "true"' to my xorg.conf.

My graphics card is: VGA compatible controller: Intel Corporation 82915G/GV/910GL Integrated Graphics Controller (rev 04)

Clearly there seems to be a problem with refresh rates. Unusually, I have been able to find absolutely no information on the internet regarding this specific behaviour.

Unfortunately this happened as part of an 'emerge world' so it is difficult to rule out a change in libdrm or xorg which could be responsible. What I can say is that booting one of my older kernels has no effect. Also, unmasking and installing x11-drivers/xf86-video-intel-2.13.0 has not helped.

I would be grateful if anyone had any suggestions regarding what I could try to properly identify the problem. Otherwise, does it seem sensible to open a bug at freedesktop.org?

Thanks for any help!

creepytennis · n00b Joined: 03 Apr 2007 Posts: 37

I've filed a bug at freedesktop.org:

http://bugs.freedesktop.org/show_bug.cgi?id=31189

They suggested the fault might lie in Mesa. Sure enough the problem disappears if I downgrade from mesa-7.8.2 to mesa-7.7.1. Could be "dri2 paths are not flushing and swapping correctly". I'll update here with any progress, especially if it turns out to be Gentoo related.

creepytennis · n00b Joined: 03 Apr 2007 Posts: 37

Hi. I've upgraded to Mesa 7.10-devel .

Running Mesa 7.10-devel without gallium solves the dri2 flushing / swapping
problem completely. :-)

Interestingly, using Mesa 7.10-devel with gallium causes the problem to return.