Downgrading xserver-xorg-video-ati from 1:6.6.3-2ubuntu3 to 1:6.6.2-0ubuntu6 solves the problem.
-- xorg fails with ati driver with feisty on Apple ppc (post herd5 update) https://launchpad.net/bugs/93509 -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
