I started seeing this bug in Ubuntu Natty, and I don't know if the cause was the same but I'm adding my experience here for others that find it via googling. In my case, it turned out that since the upgrade, my "suspend" button was now being interpreted as a "hibernate" button instead. There was no entry in gconf for a hibernate command, so it didn't know what to do.
The error in gnome-power-manager was: - action: /apps/gnome-power-manager/buttons/hibernate set to blank (The hibernate button has been pressed.) Adding a key called /apps/gnome-power-manager/buttons/hibernate and setting that to the value of "suspend" fixed the problem -- You received this bug notification because you are a member of Ubuntu-X, which is subscribed to xorg-server in Ubuntu. https://bugs.launchpad.net/bugs/410829 Title: [GM965/GL960] Pressing Suspend key turns off display instead of suspending To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/xorg-server/+bug/410829/+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