I have the same problem with GLslideShow screensaver on my laptop Sony VAIO VPCB1. I have updated from 10.10 to 11.04 yesterday and today got this problem.
-- You received this bug notification because you are a member of Ubuntu Desktop Bugs, which is subscribed to gnome-screensaver in Ubuntu. https://bugs.launchpad.net/bugs/762918 Title: Natty Screensaver freezes system after some period of inactivity -- desktop-bugs mailing list desktop-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/desktop-bugs