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

[Michel Dänzer]

On Fre, 2011-08-26 at 10:42 +0100, Martin wrote: 
> On Thu, 2011-08-25 at 11:08 +0200, Michel Dänzer wrote:
> > On Don, 2011-08-25 at 09:50 +0100, Martin wrote: 
> > > On Wed, 2011-08-24 at 08:50 +0200, Michel Dänzer wrote:
> > > > 
> > > > 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.
> > 
> > It's important to make the distinction between these possibilities
> > though:
> > 
> > Can you still trigger the hang moving the mouse interactively (e.g. with
> > a USB mouse) when psmouse was never loaded?
> 
> With no psmouse module and a USB mouse I can still trigger the fault,
> althought it takes longer, i.e. 20 minutes to 1/2 hour.

So that rules out the psmouse module being repsonsible for the hangs in
X.


> > If yes, does Option "SWcursor" in xorg.conf work around the problem?
> > (Verify in Xorg.0.log that the option takes effect)
> 
> I've set this and so far it seems to have helped.  I used the machine
> interactively for 20 minutes or so and left it running loops starting
> programs overnight.  I should hopefully have more time to use it over
> the next few days and will report back.

If the hangs don't occur with SW cursor, the attached kernel patch might
help for HW cursor with KMS.


-- 
Earthling Michel Dänzer           |                   http://www.amd.com
Libre software enthusiast         |          Debian, X and DRI developer
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