Created attachment 86071 [details]
Xorg log including sleep and wakeup cycle, as well as shutting down afterwards.

Yes exactly, the corruption occurs when the computer wakes up from
sleep/hibernation.

The behavior started at least two kernel versions ago, probably at 3.10. I
_think_ it was working with 3.8, but I will check that soon, and get back to
you.

Here's the Xorg.0.log.old from previous run. I was running for a while, and
then put the computer in sleep mode, and then awoke it immediately. When the
corruption has occurred, I shut it down normally.