> One thing that's a little strange is that sometimes the touchpad > shows up on event2 and sometimes on event3. Not sure how to deal
> with that...
You need "configured mouse" to deal with external mice that you may plug in to a USB port.
As for the event2/event3 thing, it may be that you have an external mouse plugged in that's getting event2 sometimes. There may be other
factors. You can always write udev rules to symlink the built-in devices to fixed names.
OK, this is going in the right direction. I created a file called /etc/udev/rules.d/40-personal.rules with the following contents:
# USB mouse BUS=="usb",KERNEL=="mouse?", SYMLINK="input/usb_mouse"
and changed the relevant lines of /etc/X11/xorg.conf to
Option "Device" "/dev/input/usb_mouse"
Option "Device" "/dev/input/touchpad"
Now when I reboot, the USB mouse works but the touchpad does nothing. If I then do ctrl-alt-backspace to restart X, it all works perfectly with no tap-to-click. I can live with this, though I'd be curious if there's a way to make it work without this little kludge.