https://bugs.freedesktop.org/show_bug.cgi?id=33011
--- Comment #10 from Alex Deucher agd5f@yahoo.com 2011-01-25 22:22:33 PST --- Does a dpms cycle help? xset dpms force off
Does restarting X help?
How about forcing a mode change? e.g., xrandr --output HDMI-0 --mode 1680x1050