https://bugs.freedesktop.org/show_bug.cgi?id=48880
--- Comment #5 from Alex Deucher agd5f@yahoo.com 2012-04-18 08:25:53 PDT --- If you manually add the 1920x1080 modeline with xrandr, does it work ok?
E.g.,
xrandr --newmode "my1920x1080" 148.50 1920 2008 2052 2200 1080 1084 1089 1125 +hsync +vsync xrandr --addmode DVI-0 "my1920x1080" xrandr --output DVI-0 --mode "my1920x1080"