Pretty sure this is an Xorg bug. Removing FBDev option from /etc/X11/xorg.conf fixes the problem
** Changed in: linux-source-2.6.15 (Ubuntu) Sourcepackagename: linux-source-2.6.15 => xorg-server Assignee: Ben Collins => (unassigned) -- 2.6.12 and above create 100% CPU with xorg on iMac https://launchpad.net/bugs/22667 -- kubuntu-bugs mailing list kubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/kubuntu-bugs