For some years now I've suffered from an intermittent bug in the X server: the mouse freezes, then jumps continually between the edges of two adjacent displays. The X server uses 100% CPU time. I haven't found any way to recover from this situation: I need to stop X, which involves connecting from a different machine.

I've researched this and found a number of leads, none of which is specific enough. The problem happens almost only with nVidia cards, but also under other operating systems. As far as I can see, it also requires at least two display cards and the proprietary nVidia drivers, but I can't be sure about that.

Here's what I've found so far:

• This video clip shows the effect I'm getting

• A bug report against Ubuntu. It blames it on a new version of Ubuntu (10.4), which is clearly incorrect; presumably it has something to do with the version of X or the nVidia drivers supplied with this version of Ubuntu. There's a lot of discussion, but it seems to miss the point.

• Another report, also related to Ubuntu. Entry 9 is a report from somebody claiming to get it using non-nVidia hardware.

• The previous report also references this bug report, which appears to have nothing to do with the issue.

• This one, with Red Hat, has a

There are also a number of references which I think are not related:

• This is a reference to a recoverable situation using SuSE. This appears to be a copy.

I'll add to this page as I discover more information.