nvLock: client timed out, taking the lock
I've been seeing this problem once in a blue moon since I got my current laptop (GeForce Go 7600).
The symptom is that X freezes completely for ~10-20 seconds when opening or moving a window. Eventually it unfreezes and I see the message "nvLock: client timed out, taking the lock" appear in the X log file.
This looks to me like one of those "if you see this, please file a bug" kind of messages, so here's a bug report log file. If it would help I can try to cut down my code to a standalone example; would this be worth it? The bug only occurs very rarely - often I have to run my application for several hours before it shows up.