I have this same issue... I added it to this bug report https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video- ati/+bug/225863. Have you tried pinging the machine after the screen goes black to check if its a complete lockup or just an x crash.
-- "No Signal" Integrated ATI Radeon 7000 graphic core with Acer AL1916W https://bugs.launchpad.net/bugs/222544 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
