Comment 29 for bug 446578

I can report that forcing the install of 7.6.0-1ubuntu2~bug446578~1 on my notebook PC with ATI Radeon Xpress 200M graphics chip has solved the problem thus far. I can (re)enable compositing and desktop effects on Kubuntu Karmic Beta with KDE 4.3.2 and not experience the crash back to kdm login screen.

I am running the latest kernel 2.6.31-13. So I tried both booting without Radeon KMS enabled and with "radeon.modeset=1". Enabling "radeon.modeset=1" slows down my system, but on the other hand, leaving Radeon KMS off by current default creates the situation whereby I can see certain visual artifacts on the screen.