https://bugs.freedesktop.org/show_bug.cgi?id=28671
--- Comment #11 from Alex Deucher agd5f@yahoo.com 2010-06-22 23:04:50 PDT --- Actually, your lockups are probably AGP related. Try adding radeon.agpmode=X to your kernel command line where X = -1 or 1 or 2 or 4 or 8, e.g., radeon.agpmode=1 and see if any of those help.