> Does it work if you boot without X and modprobe nouveau manually? If it does,
> can you disable page flipping in xorg.conf (Option "PageFlip" "0" in nouveau
> device section) and recheck with X?

It happens long before X, when the nouveau module is loaded.

> Does it work if you disable acceleration (nouveau.noaccel=1 in kernel command
> line)?

nouveau.noaccel=1 is already on my cmdline as running X with accel 
enabled never worked anyway.

 > Is there anything saved in /var/log/ from previous boot? Can you ssh
> into and check dmesg? Can you use netconsole and catch full log?

Thanks for the netconsole tip. I have attached the log.

I am not an expert but it looks like a crash in the inlined 
nouveau_software_vblank(). Is the vblank.list already initialized at 
this point?

Thanks,

Ortwin