lost mouse functionality in 2.6.x kernel upgrade

[James Miller <jamtat@mailsnare.net>]

I've tried upgrading to the 2.6.x kernel on my Debian Sid system a couple
of times now, but each time I boot into the gui with the new kernel, I
lose all mouse functionality.  In other words, no matter what I do to the
physical mouse, the cursor on the screen will not move: it just stays
stuck there in the middle.  This is just a regular old ps/2 mouse.  I've
upgraded several 2.4.x kernels and never had any mouse problems.  I do
have gpm installed, and the configured mouse in XF86Config-4 points to
/dev/gpmdata.  So far, I've tried commenting out the generic mouse section
of XF86Config-4 which, as I understood, is meant to enable USB mice (which
I don't have) and its corresponding entry in the ServerLayout section.
But that did not resolve the problem.  I'm currently trying to use the
2.6.4 kernel.  Can anyone help me to resolve this problem?

Thanks, James