Comment 4 for bug 537741

Forwarded from Launchpad: https://bugs.edge.launchpad.net/ubuntu/+source/xserver-xorg-video-nouveau/+bug/537741

Whenever something graphically intensive happens (except, apparently, video) like compositing, a gpu lockup occurs, freezing X and even terminal switching but allowing use of SysRq commands. Can sometimes switch terminals by first pressing Alt-SysRq-K. Only occurs with an NV18 card; NV17 works fine, for example.

I have enabled compositing in Metacity. One test was selecting the Applications menu and rapidly switching through that and Places and System, which eventually froze X. After doing Alt-SysRq-K, it allowed me to log back in, and I tried again with no problem; I opened some semi-transparent terminals, enlarged them, and moved them around over eachother. Trying to enlarge the ~eighth terminal froze X. Eventually I had a kernel panic. Occasionally I can't even boot fully. Sometimes X will freeze and allow cursor movement, other times won't. Has occured a couple times in a (Ctrl-Alt-F1...) virtual terminal.

Often I see colorful flashing as textures load, particularly at boot. Once I rebooted and seen the screen as it was when X froze, for a few seconds, and it cleared and finished loading GNOME.

I suppose there is a chance the card is defective...but it has no problem with the NVIDIA binary drivers. (As an aside, I even had Compiz running in Nouveau for some durations before freezing.)

Xorg log: http://launchpadlibrarian.net/40822534/XorgLogOld.txt
Boot dmesg: http://launchpadlibrarian.net/40822504/BootDmesg.txt
dmesg around the freeze & SAK recovery: http://launchpadlibrarian.net/40822506/CurrentDmesg.txt
lspci: http://launchpadlibrarian.net/40822515/Lspci.txt