EH:
  Just finished configuring a custom kernel. At the opms line --
which was the problem -- I noticed the following message:

[239] # "opms" should not be enabled together with "pms" or "pmsi"

Anyways, I commented all of them out, I don't use them to drive my mouse.
Its connected via a serial port (tty01); I seem to remember configur-
ing it somewhere in /etc/XF86Config...