from looking at your xorg.0.log i assume this is a duplicate of : https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-intel/+bug/120834 see the description i created for details
from looking at your xorg.0.log i assume this is a duplicate of : /bugs.launchpad .net/ubuntu/ +source/ xserver- xorg-video- intel/+ bug/120834
https:/
see the description i created for details