6532eb17baff6e61b427f29e076883f8941ae664 is not the cause of this bug (or
damaged the hardware, but let's think positive for now) as I just had the exact
same thing with a older mesa version. Also this seems to be connected with all
other bug reports I listed above, especially the "GPU fault detected" from
here: https://bugs.freedesktop.org/show_bug.cgi?id=58667

I'm still pre-bisecting (searching for a good commit) but as this bug sometimes
needs hours to get triggered this may take very long.