Comment # 22 on bug 63599 from Paul Wolneykien

(In reply to comment #21)
> That just disables the use of vram for exa pixmaps.  You can accomplish the
> same thing by adding:
> Option "EXAPixmaps" "false"
> to the device section of your xorg.conf

  Yes, the option helps a little: I can see the KDM screen without any
artifacts. However, it is dead, i.e. frozen. Feels like a GPU lockup, but no
error messages in Xorg log or dmesg. How can I get more info?