(Problems with mouse, Belkin KVM switch and Linux)

I've got a Belkin KVM switch which I use to swap between various machines by my desk. I really like it as I can share a monitor, keyboard and mouse between different machines at a press of a button. When I was switching between two windows machines there was no problem, but I have been getting a problem with linux.

The worst problem shows itself when I switch into Linux and mouse goes haywire, moving around at random and clicking buttons. If this happens I can get things back to normal by switching in and out of another virtual console.

(If that means nothing to you, here is the long explanation. Linux boxes have multiple virtual consoles. If you are in text mode you can switch between these by pressing alt-f1, alt-f2 etc and get a different login. If you are in X windows you use ctrl-alt-f1 etc. To get back to X you keep pressing alt-f1, alt-f2 etc till you find which virtual console displays X - in my case (debian) it's alt-f7. So I get out of trouble my going ctrl-alt-f5 followed by alt-f7. I don't know why I use f5 on the first key press, anything from 1-6 should work.)

Switching in and out of virtual consoles is a pain, of course. I've been playing around with installs recently and noticed some did had this mouse madness and some didn't. I haven't done any detailed troubleshooting on this, but I did swap the mouse definitions in my XF86Config file.

The one that had a problem was from a RedHat 9 install.

Section "InputDevice"
        Identifier  "Mouse0"
        Driver      "mouse"
        Option      "Protocol" "IMPS/2"
        Option      "Device" "/dev/psaux"
        Option      "ZAxisMapping" "4 5"
        Option      "Emulate3Buttons" "no"
EndSection

I changed this to

Section "InputDevice"
        Identifier  "PS/2 Mouse"
        Driver      "mouse"
        Option      "Protocol" "auto"
        Option      "ZAxisMapping"          "4 5"
        Option      "Device" "/dev/psaux"
        Option      "Emulate3Buttons" "true"
        Option      "Emulate3Timeout" "70"
        Option      "SendCoreEvents"  "true"
EndSection

This came from a morphix install. (The Morphix install had other problems with my monitor.) I won't try to figure out what the important change is, I'm pretty ignorant of X and would like to be more so.

To make the change visible in the file I changed another section from

Section "ServerLayout"
	Identifier     "Default Layout"
	Screen      0  "Screen0" 0 0
	InputDevice    "Mouse0" "CorePointer"
	InputDevice    "Keyboard0" "CoreKeyboard"
	InputDevice    "DevInputMice" "AlwaysCore"
EndSection

to

Section "ServerLayout"
        Identifier     "Default Layout"
        Screen      0  "Screen0" 0 0
        InputDevice    "PS/2 Mouse" "CorePointer" #imported from Morphix install
        InputDevice    "Keyboard0" "CoreKeyboard"
#commented out as Morphic didn't have it
#       InputDevice    "DevInputMice" "AlwaysCore" 
EndSection

Now I don't have mouse jigger problems on that machine. However when I do switch in the mouse won't respond till I shake it around a bit - I can live with that. Sometimes it's been a while before it responds and switched in and out of the windows box and/or the virtual consoles before it responds. I can live with that too.

One day I hope someone or something will make configuring X as easy as it is to get windows to work. At the moment this is one of the most painful parts of using Linux as a desktop machine.