This question is a followup for this [one].1 I've identified the problem as being related to different xorg driver versions. My /etc/apt/sources.list file on the upgraded system is as follows: # deb cdrom:[Ubuntu 12.04.2 LTS _Precise Pangolin_ - Release amd64 (20130213)]/ dists/precise/main/binary-i386/ # deb cdrom:[Ubuntu 12.04.2 LTS _Precise Pangolin_ - Release amd64 (20130213)]/ dists/precise/r
![Ubuntu 14.04 LTS sources.list contents](https://cdn-ak-scissors.b.st-hatena.com/image/square/664a2d3dc991972667a15e0e849615b9670c436b/height=288;version=1;width=512/https%3A%2F%2Fcdn.sstatic.net%2FSites%2Faskubuntu%2FImg%2Fapple-touch-icon%402.png%3Fv%3Dc492c9229955)