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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?

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I've had similar issues with Gentoo. Not sure why it happens, but it is definitely larger than just Ubuntu. – Jarvin Jul 7 '10 at 17:40
Did you try removing and putting back in the mouse without the KVM ? if it has the same behaviour then it has nothing to do with the KVM. Otherwise the mouse driver Linux uses for the KVM emulated mouse is not perfectly compatible with your KVM. – Ioan Paul Pirau Aug 27 '11 at 8:45
I got rid of the tower and the KVM over a year ago, Ioan. – CarlF Aug 28 '11 at 0:54

Ok, I don't have an answer for your hardware kvm question, but I might suggest that you look at synergy as a solution to your 'share keyboard and mouse' between two computers.

Synergy is a lightweight client server app that uses the keyboard and mouse on the server to move the pointer and allow text input on client machines. It also allows cut and paste between machines.

Geometry and location of video screens is configured in a text file on the server, allowing, for instance, the monitor for your tower to be placed 'above' the monitor for the laptop. When you move the mouse pointer off of the top of your laptop, it enters the bottom of the monitor for the tower...

Synergy can be found here: Servers and clients are available for PC, Linux and Mac.

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The problem is that some inexpensive KVMs will disconnect the USB peripherals when switching between systems. Reconnecting a USB device is not necessarily going to result in a device that works immediately as there are many subsystems that are invoked. Contrast this to PS/2 which was an "always on" protocol that never had this sort of problem with KVMs.

Your best bet will be to do one of the following:

  1. upgrade your kernel and udev, possibly upgrading from Ubuntu 9.10
  2. replace your KVM with a PS/2 KVM (if you have PS/2 on your systems)
  3. replace your KVM with one that maintains USB connections.
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The problem is, as mentioned in another comment, long over for me personally. I don't use a KVM any more and don't use 9.1 any more either. – CarlF Jan 13 '11 at 17:31

What brand of mouse and KVM? I've noticed issues with anything other than logitech mice with both a Startech PS2 and a Trendnet USB KVM. Or OEM mice that are made my Logitech.

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