https://bugs.freedesktop.org/show_bug.cgi?id=42913
--- Comment #3 from Kai debian@carbon-project.org 2011-11-15 11:47:33 PST --- (In reply to comment #2)
does xrandr to a new mode and back help?
Yes, that restores a normal screen. AFAICT there is no vestige of the corruption left.