(In reply to comment #10)
> Just to be clear is it a problem specifically with HDMI or using any
> display?  Also make sure you fully uninstalled fglrx.  It overwrites some of
> the libs on your system with it's own versions.  You can also try disabling
> acceleration.  Add:
> Option "NoAccel" "true"
> to the device section of your xorg.conf

It's a problem using any connector, VGA being another one I've tried. I did the
installation by these instructions to the point, so I shouldn't have fglrx
installed (http://forum.xbmc.org/showthread.php?tid=174854).
I can try without acceleration if that's fruitful for debugging, but that's not
a useful end result for me.