I finally got my mouse working on Ubuntu. I have a two-button Logitech serial mouse attached to the on-board serial port 1, listening on COM4 (yes, I know, old skool, but I'm cheap and it still works perfectly). For whatever reason the install routines did not properly detect the mouse. Here's what I had to do to get it working.

  • At the Gnome welcome screen, alt-s to bring up the session dialog.
  • Choose whatever terminal option is there, and alt-o for OK.
  • Enter username/password.
  • vi /etc/X11/xorg.conf
  • Look for the "Section InputDevice" that sets up the mouse.
  • Change Option Device from "/dev/input/mouse" to "/dev/ttyS0" (that is tty+capital S+number zero).
  • Change Option Protocol from "IMPS/2" to "Auto".
  • There were 2 other options in the mouse section, but I left them as they were.
  • Hit ESC to get back into command-mode.
  • type ":wq" no quotes, to quit VI, writing changes.
  • At the terminal type halt to restart the machine. (You could probably just tell X to restart itself, but I'm a Windows luser, so I'm used to rebooting my machine when I change 2 lines in a config file

I found help on Ubuntu forums that referenced editing /etc/X11/XF86Config-4 however, that file no longer exists on the latest Ubuntu release. The corresponding file is the one listed above.

The help I found also suggested that the number after the ttyS is equal to n-1 where n is the COM port the mouse is on. However, in my case, n is equal to the ordinal number of the onboard serial ports (so, serial port 1 is ttyS0 and port 2 is ttyS1, regardless of COM ports).