This sounds like the same symptoms as bug #546678. Do you guys still get the same issues if you 'sudo apt-get purge gnome-screensaver' ?
Another workaround was to run 'xgamma -gamma 1.0' when the black screen occurs (see https://bugs.launchpad.net/ubuntu/+source/xorg- server/+bug/546578/comments/15). -- Logout after switch user cause black screen https://bugs.launchpad.net/bugs/561538 You received this bug notification because you are a member of Ubuntu-X, which is subscribed to xorg-server in ubuntu. _______________________________________________ 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