These Radeon Xpress 200 cards seem to be a real problem! I've just upgraded to Dapper and I'm having the same issue with the same card, on gdm. Using my old Breezy kernel seems to be a temporary solution, but a quick check of glxinfo reveals that Direct Rendering is turned off when I use the Breezy kernel. The open-source ATI and Radeon drivers have never worked for me.
-- Lockup problems with both the free xorg ATI driver and the proprietary fglrx driver, using various ATI cards https://launchpad.net/bugs/30447 -- kubuntu-bugs mailing list kubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/kubuntu-bugs