I plug my old serial mouse with Microsoft protocol into COM1
(ttyS0). Here is my configuration:
Section "InputDevice"
Identifier "Mouse1"
Driver "mouse"
Option "Protocol" "Microsoft"
Option "Device" "/dev/ttyS0"
Option "Emulate3Buttons"
Option "Emulate3Timeout" "50"
EndSection
My serial mouse works fine in Debian Etch xorg!
$ lsmod | grep "8250"
8250_pnp 8704 0