Comment 3 for bug 26825

this is still an issue in edgy.
as heiko mentioned, there is no generic device for evdev (or at least i'm not aware of such thing).
so if you set up your mouse with evdev you have to specify something like

Option "Device" "/dev/input/event1"

but the problem is, your pointing device isn't always 'event1' if you're hotplugging your devices.

hth