Due to bug 919398 wondering if they're related. The graphics corruption was always colourful or rather it displayed the broken user background image. Recently it's black instead, same as the window underneath, it doesn't display a broken user background image.
** Attachment added: "greeter2.png" https://bugs.launchpad.net/lightdm/+bug/933322/+attachment/2776455/+files/greeter2.png -- You received this bug notification because you are a member of Ubuntu-X, which is subscribed to xserver-xorg-video-ati in Ubuntu. https://bugs.launchpad.net/bugs/933322 Title: LightDM graphic corruption with ati and nvidia To manage notifications about this bug go to: https://bugs.launchpad.net/lightdm/+bug/933322/+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