I use a KVM switch to jump between my tower and laptop, both placed on my desk. With Ubuntu 9.04 this worked perfectly. In 9.10, when I switch to the tower, then back to the laptop, the mouse is detected (as shown by /var/log/messages) but moving it has no effect. If I use Ctrl-Alt-F1 to switch to the TTY, then Alt-F7 back to Xorg, the mouse starts working.
The tower is running Windows 7, but that shouldn't matter.
Sometimes, but not other times, the USB keyboard on the KVM switch is also not usable and I have to use the laptop's built-in keyboard to switch to the TTY.
The laptop has two monitors, the built-in and an external. It's (obviously) the external panel that is attached via the KVM switch.
Any suggestions? Report to Canonical as a bug?