On several boxes fitted with ASUS GT520 Silent graphic cards is see the following problem.
When I start X it works fine the first time. However, when the X server is restarted (eg after a logout) the second (and subsequent) time the Xserver is totally unresponsive. Clients (such as xdpyinfo) connect to the server successfully, but hang indefinitely. If the client is kdm, it eventually times out and kills the server. After a few tries kdm disables the server.
After the first execution of the Xserver, and before the second execution, things are apparently normal, but after the second execution, vt switching doesn’t work and it is impossible to do anything on the console. It is possible to log in remotely, but killing the X server does not restore the virtual terminals (vt).
This problem an identical software configuration works properly with a GeForce 8600M GT and a GT218 [ION] GPU.
This is with a version 304.64 driver, but it also occurred with earlier versions. I am not able to confirm whether or not this problem has always existed with the ASUS GT520 Silent cards or whether it is unique to those cards.
I have the output from two runs of nvidia-bug-report.sh for the first and second executions of the server. In both cases the server was running while the bug report was prepared (although in the second case the server is not responding). However, when I try and attach the log files I get an error message about an invalid extension.