May the bug should be filed against xorg and not the ati driver. I have a similar if not an identical problem but with the VIA UniChrome chip.
1) Install Kubuntu Jaunty and update to the latest packages and install and enable sshd. Boot latest kernel. 2) Login. Logout. Login. Logout. Screen now goes blank, keyboard does not respond anymore, ctrl+alt+backspace does not kill X. 3) ssh into box. 'sudo killall -HUP kdm' to 'resolve' blank screen after second logout attempt. Login screen should now appear. (or I guess switch to a terminal except that Ctrl+Alt+F1 did not work for me) ** Attachment added: "kdm.log" http://launchpadlibrarian.net/33114906/kdm.log -- [HD3300] Kubuntu: logout crashes X on AMD64 https://bugs.launchpad.net/bugs/367053 You received this bug notification because you are a member of Ubuntu-X, which is subscribed to xserver-xorg-video-ati in ubuntu. _______________________________________________ Mailing list: https://launchpad.net/~ubuntu-x-swat Post to : ubuntu-x-swat@lists.launchpad.net Unsubscribe : https://launchpad.net/~ubuntu-x-swat More help : https://help.launchpad.net/ListHelp