First, let me explain why I'm pretty sure this is an issue unique to Debian:

1. I've been using my KVM switch without issue in both Slackware 9.1-11, and Fedora 6.

2. I've tested the usb mouse without the KVM switch and it works without issue

3. I have tested multiple mice, and confirmed this is not an issue with a specific mouse.

Here's what I'm using:

GWC USB2 4PORTS KVM SWITCH KC234H R

Here's what happens:

When I move the mouse, it's a delayed response. The mouse doesn't move initially, and when it does move, normal acceleration occurs. When I have to move the mouse and stop in anticipation of where the cursor will end up. I have tried changing the settings on the mouse such as sensitivity and acceleration with no improvement on performance.

If anyone has any suggestions, either on where to check for significant errors, or on how to resolve this issue, it is greatly appreciated.

Mice are cheap. Forget figuring out what's wrong (it's a KVM issue, thus should be addressed by it's manufacturer: chances are slim they'll do) and get yourself some usable mice to connect directly to the connected PC's. Does the KVM has a web-interface to configure it? If so, experiment there with it's settings.