I asked nVidia the same question and they told me that their forum is their bug tracker.
http://www.nvnews.net/vbulletin/showthread.php?s=608ff3cf670e498bc114a281d973d45e&t=46678 -- [nvidia] compiz displays white screen when locked https://bugs.launchpad.net/bugs/160264 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs