If your serial mouse does not work try using kermit
or
tip
to connect to the mouse serial port and verify that it
does indeed generate characters.
The OpenBSD pms driver provides both ``raw'' and ``cooked''
(translated) modes. ``raw'' mode does not do protocol translation, so
XFree86 would use the PS/2 protocol for talking to the device
in that mode. ``Cooked'' mode is the old BusMouse translation.
The driver runs in ``raw'' mode when using the /dev/psm0
device name.
On OpenBSD 2.2, only standard PS/2 mice are supported by this driver.
On OpenBSD 2.3 and later include there is support for recent PS/2 mice that send more than three bytes at a time (especially intellimouse, or mouseman+ with a "3D" roller).
See README.mouse for general instruction on mouse configuration in XFree86.