Bug#424941: xserver-xorg-video-i810: screen corruption and machine hang when accessing xv downgrade helps
> I am using the latest unstable (also experimental) and after the last
> upgrade xorg produces weird results.
> If I play a movie with mplayer the movie window is filled with blue (xv
> issue?) and after exiting mplayer the whole screen is filled with colored
> vertical lines and the machine hangs.
This is a known bug. You're right, it is an Xv issue, and so the
simplest workaround at the moment is to configure your player to use
plain X11 output rather than Xv output.