Hi, After doing a full-upgrade on my sid this morning, I am encountering the very same problem. I am not using radeon but nvidia module, but it looks like the same : everytime I launch a KDE app (or QT ?), X crash and restart. No problem so far with non KDE apps.
Don't know if this problem should be resolved in xorg or KDE, but just to say that Serge is not alone facing this problem. The crash Xorg.log is attached. Best regards.
Xorg.0.log.old
Description: application/trash
