Hi everyone, I can confirm this issue, too. Only difference - my platform is still i386.
On the one hand it renders KDE quite unusable and on the other hand I get many segmentation faults for GTK related stuff when I try to use other window managers instead of KDE, which renders them quite unusable, too. As side effect I lost some parts of my KDE configuration (desktop/folder settings configuration) during first login without running kwin.
Hence I added a suitable link as quick and dirty workaround to get KDE up again.
Best Regards Martin -- To UNSUBSCRIBE, email to debian-bugs-rc-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org