Two of my machines have USB mice.  On occasion, and without apparent 
cause, the system will stop seeing any mouse events.  Usually, 
unplugging the mouse and reconnecting it will solve the problem; 
sometimes, though, I have to reboot.  Any suggestions on the cause (or 
a fix)?  

I'm running -current with xorg on new Dell Dimension 8400s, with ITAC 
Systems Mouse-Traks.

		--Prof. Steven M. Bellovin, http://www.cs.columbia.edu/~smb