This should was fixed by kde-window-manager 4:4.5.1-0ubuntu3 with the change:
* Add kubuntu_29_fallback_to_xrender_compositing.diff fallback to XRender compositing in case of Software Rasterizer. (backport from trunk) ** Changed in: xserver-xorg-video-nouveau (Ubuntu) Status: New => Fix Released -- KDE does not start; thrown back to login screen https://bugs.launchpad.net/bugs/638817 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs