Kernel-xen issues. Can't use X due to graphics lock up / system failure.

[Naoki]

In short : Running 2.6.18-1.2798.fc6xen (I've also tried many older
versions ) the system starts up and is usable in multiuser mode. However
under init 5 (X) screen corruption occurs and the system locks.

The messages dump looks very similar so I'm re-opening :

https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=207432

Anybody else see this?