login screen has erratic behaviour and visual artefacts

[Michael Andersen]

When I start up my PC, I see strange artefacts on the login screen, pressing keys causes the artefacts to change (for instance pressing 'H' causes a few more white spots to appear, and pressing backspace causes them to disappear). Half the time when I log in, it either freezes and fails to log in or it crashes and restarts the login screen.

I am using a standard Ubuntu 12.04 that is up to date (as of 21 May 16h30) but I do have the nvidia restricted drivers activated.

As an aside, I have another machine which is 11.10 which also gets artefacts on the login screen, but pressing enter causes the login screen to restart and they go away. On 12.04 this is not the case. The other machine is also using the nvidia restricted drivers.

I don't know which logs to attach, so let me know. It is fairly reproduceable.

[Michael Andersen (mpandersen)]

I took a few pictures of it so you can see what I mean.
This image is after typing in the password: http://imgur.com/aTTOg
This image is after switching to a VT. I know it actually switched because I blindly logged in and shutdown in the terminal, but you can only see garbage on the screen: http://imgur.com/YkEP7

[Michael Andersen (mpandersen)]

As a further aside, I just deactivated the nvidia driver and I still get get the artefacts (albeit at a hideously inappropriate resolution for my screen) so perhaps the nvidia drivers are irrelevant.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.