This was reported in Ubuntu by Mike Agnew. He has done lots of debugging, including gdb which doesn't seem to bite on Xorg. He has now updated to xorg-server 1.3 and ati driver 6.6.192 on top of Ubuntu Feisty. When the server starts, the screen goes black and the keyboard is locked up. This only happens when DRI is enabled. He can ssh from another machine and sees that Xorg is eating CPU time. He has tried sysrq-trigger, but we can not see Xorg in the trace. If attaching with gdb, it's not possible to stop it with ctrl-C and gdb turns bad. He also set the debug option on the drm module and logged from /proc/kmsg.
Created attachment 10274 [details] Xorg.0.log
Created attachment 10275 [details] syslog with sysrq trace
Created attachment 10276 [details] kern.log with drm debug=1
can he try with Option "BusType" "PCI" It looks like an AGP issue.
As mentioned in the summary, it is a PCI card.
*** This bug has been marked as a duplicate of bug 10874 ***
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