OK, thanks to George's tip I finally solved the problem just disabling "tear-free" in catalyst center (admin mode) and the configuration proposed in the workaround:
(obviously with the proprietary ATI fglrx) 1. Open Catalyst Control Center (admin mode). 2. Display Options -> Tear Free-> disabled 3. Go to 3D > More Settings. 4. Set "Wait for vertical refresh" to "On, unless application specifies". With tear-free enabled, I always get compiz at 100% inmediatly when close the lid of my laptop or 30 minutes after (aprox). I've tried to replicate the problem many many times with tear-free disabled but is imposible, now is working flawless. My laptop and compiz process enjoys a cool and quiet idle mode indefinitely. I suppose that "tear-free" is enabled by default in the opensource driver, this would explain why this occurs with this driver too. ___________________________________________ Ubuntu 12.04 Catalyst Control Center: 12.4 Driver package: 8.96.7-120312A-135598c-ATI 2D Driver: 8.96.4 -- You received this bug notification because you are a member of Ubuntu-X, which is subscribed to fglrx-installer in Ubuntu. https://bugs.launchpad.net/bugs/969860 Title: fglrx uses 100% CPU when screen turns off (spinning in glXWaitVideoSyncSGI or glXSwapBuffers) To manage notifications about this bug go to: https://bugs.launchpad.net/compiz/+bug/969860/+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