Comment 1 for bug 507504

Can you please attach the output of "lspci -vvnn" to this bug report. After that, wait until it happens again... when it hangs, please login via ssh from another computer; once logged into the hung computer save the contents of "dmesg" plus copies of the files "/var/log/X*" and attach those to the bug report as well.

Finally, please collect a batch buffer dump recorded on the hung machine. The specific steps required to do this is described here:
https://wiki.ubuntu.com/X/Troubleshooting/Freeze#How%20to%20Get%20a%20Batchbuffer%20Dump%20%28-intel%20only%29

PS, I started to experience a similar hang on lucid just yesterday.