This may well prove to be a duplicate of bug 246836. Can you attach your xorg.conf, Xorg.0.log, output of 'sudo ddcprobe' and output of 'xrandr'?
This may well prove to be a duplicate of bug 246836. Can you attach your xorg.conf, Xorg.0.log, output of 'sudo ddcprobe' and output of 'xrandr'?