Hi, this happens to me also in Ubuntu 13.04. Sometimes it happens when the screensaver is active, but sometimes it happens even when I'm working with the computer. In the second case I can go to console and restart the lightdm service, but in the first case I have to REISUB to make things work again.
-- You received this bug notification because you are a member of Desktop Packages, which is subscribed to gnome-screensaver in Ubuntu. https://bugs.launchpad.net/bugs/762918 Title: Natty Screensaver freezes system after some period of inactivity Status in Linux ACPI client: New Status in X.org xf86-video-intel: Confirmed Status in “gnome-screensaver” package in Ubuntu: Incomplete Status in “linux” package in Ubuntu: Incomplete Bug description: Binary package hint: gnome-screensaver When selecting "Floating Ubuntu" screensaver, after a period of inactivity greater than 40min, the systems locks itself and becomes unresponsive. ProblemType: Bug DistroRelease: Ubuntu 11.04 Package: gnome-screensaver 2.30.2-0ubuntu2 ProcVersionSignature: Ubuntu 2.6.38-8.42-generic 2.6.38.2 Uname: Linux 2.6.38-8-generic x86_64 Architecture: amd64 Date: Sat Apr 16 13:04:12 2011 EcryptfsInUse: Yes GconfGnomeSession: idle_delay = 5 /desktop/gnome/session/required_components: windowmanager = gnome-wm GnomeSessionIdleInhibited: No GnomeSessionInhibitors: None InstallationMedia: Ubuntu 10.10 "Maverick Meerkat" - Release amd64 (20101007) ProcEnviron: LANGUAGE=en_US:en LANG=en_US.UTF-8 SHELL=/bin/bash SourcePackage: gnome-screensaver UpgradeStatus: Upgraded to natty on 2011-04-15 (1 days ago) WindowManager: gnome-wm To manage notifications about this bug go to: https://bugs.launchpad.net/acpi/+bug/762918/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : [email protected] Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp

