Bug#637958: X.org crash leaves GPU in an inconsistent state and renders system unbootable

[Martin <mjb@cs.bath.ac.uk>]

On Wed, 2011-08-24 at 08:50 +0200, Michel Dänzer wrote:
> On Die, 2011-08-23 at 23:14 +0100, Martin wrote: 
> > On Thu, 2011-08-18 at 13:10 +0200, Cyril Brulebois wrote:
> > > Martin <mjb@cs.bath.ac.uk> (18/08/2011):
> > > > The instructions work but the packages will not install due to a
> > > > dependency problem.  If I understand correctly what's happening is:
> > > > 
> > > > *. Part of the xorg core breaks *-video-6
> > > 
> > > Because src:xorg has not reached squeeze-backports yet. Uploaded a few
> > > hours ago (src:xorg needed to reached testing before it could be
> > > backported, hence the delay compared to mesa, xorg-server, and drivers).
> > > 
> > 
> > Right; have upgraded to the latest X.org and kernel in backports and the
> > problem still persists.  Something causes the machine to hang while
> > bieng used interactively in X and after this loading the kernel psmouse
> > module hangs the machine.
> > 
> > What should I try next?
> 
> Can you try if the hangs in X happen when the psmouse module is never
> loaded in the first place?

So I've tried the following:

1. Boot from a Debian 4.0 install CD to clear the non-volatile fault.

2. Boot from a Debian 6.0 install CD to blacklist psmouse without
loading it.

3. Reboot the system and let X start.

4. Log in via SSH and run four separate loops, each of which starts a
set of programs, sleeps for a prime amount of time, kills them and sleep
for another prime amount of time.  One loop ran five xterms, one ran two
glxgears (one fullscreen) and one ran twenty xeyes while the final loop
ran a fulscreen mplayer.  When I have run this kind of load
interactively it hangs the machine within 20-30 minutes, run via SSH it
ran stably for over 12 hours.

Thus I conclude that the thing that triggers the bug is dependent on
psmouse or (inclusive-or) interactive use of the machine via keyboard
and mouse.

I'm beginning to think that this is more like a kernel / psmouse /
X-input bug a less of a graphics bug.

Cheers,
 - Martin