Comment 48 for bug 986524

I get the mentioned output when X locks up (mouse movement excluded) running with a radeon x1600 video card, Gallium 0.4 on ATI RV530. I usually manage to get to tty* to see the error repeatedly posted and sometimes, with the addition of "[drm:radeon_cs_chunk] *ERROR* failed to schedule IB!".

Circumstances around error:

To elaborate on the conditions around the time of the error, I can tell you you that I've noticed the problem when running shadows, transparency, transitions, fadings, and menu transparency via Compton, and shadows, fadings, and transparency via xcompmgr.

While I write this, X is working functions properly but dmesg | garep radeon outputs:

radeon 0000:01:00.0: registered panic notifier ... [drm:radeon_cs_ib_chunk] *ERROR* Invalid command stream !

From there, killing the desktop session throws me back into a visually scrambled lightm, and the error continues to show up in tty1*. Doing sudo service lightdm restart (from tty*) does not alleviate the problem.

I don't catch any other errors. /var/log/Xorg.0.log does not report any (after a reboot, mind you) other than complaining, "Failed to load module "fglrx" (module does not exist, 0)" twice, but it's normal --or so I've been told by a Ubuntu dev.

Thoughts:

Since I no longer use unity desktop and compiz but xcompmgr and compton, and I've gotten the error with both of the latter, I can assume it's not a compositor issue. I should say that I used to get compiz (and Unity) crashing all the time two years ago or so, the reason why I stopped using Unity, but I can't say I ever noticed this particular error back then. I've been happily using OB with xcompmgr for the past two years or so, untill now.

I've always assumned the problems with Unity were video driver issues. So there's my two bits. Hopefully a savy dev can make sense of the source of the problem and issue a patch both locally and upstream.

I'm running Raring by the way.