https://bugzilla.kernel.org/show_bug.cgi?id=42678
--- Comment #18 from Michel Dänzer michel@daenzer.net 2012-05-04 13:08:18 --- (In reply to comment #15)
I can reproduce the lockups easily by switching from my 2 monitors in default mode to dual screen mode. Lockups start happening right away.
Note that this bug report isn't about lockups per se but about the inability to recover from a lockup. You should probably look for another bug report about monitor switching causing lockups, or file your own.