I observe a similar behavior on 2.6.36.1 and 2.6.37-rc3. The gdm login window locks up for 20 seconds and then gets released. With kdm the lockup seems to be either longer or permanent. It does look like kms+gdm problem. Mine is intel's i915.
** Changed in: gdm (Ubuntu) Status: New => Confirmed -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/580755 Title: Login screen locks up; mouse & keyboard are disabled -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs