This is a known race in pageflip vs dpms off/modesetting, should be fixed in raring and backported.
** Changed in: xserver-xorg-video-intel (Ubuntu) Status: New => Fix Released -- You received this bug notification because you are a member of Ubuntu-X, which is subscribed to xserver-xorg-video-intel in Ubuntu. https://bugs.launchpad.net/bugs/1097371 Title: lock screen blank in Ubuntu 12.04 xserver-xorg-video-intel update not working To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-intel/+bug/1097371/+subscriptions _______________________________________________ Mailing list: https://launchpad.net/~ubuntu-x-swat Post to : ubuntu-x-swat@lists.launchpad.net Unsubscribe : https://launchpad.net/~ubuntu-x-swat More help : https://help.launchpad.net/ListHelp