[svlug] KVM problems

josh joshw at speakeasy.net
Tue Aug 20 16:11:11 PDT 2002

Tuesday, August 20, 2002, 2:54:47 PM, Dan wrote:

DM> Josh wrote:

>> When I switch to linux using the kvm switch, if linux is running X,
>> it screws up the mouse, causing wild movements and uncalled-for
>> spontaneous clicking. Here's a sample scene:

DM> I've had this problem, too. The root cause is that the Explorer
DM> supports multiple versions of the PS/2 mouse protocol: one in which it
DM> behaves like an older member of the MS mouse family, for backward
DM> compatibility, and one in which the fourth and fifth button are
DM> accessible.

DM> When talking to Windows, it goes into the latter mode; when you switch
DM> to Linux, X tries to talk to the mouse using the older protocol, but
DM> the mouse has already decided that it's using the newer one. Much
DM> confusion ensues.

DM> What Protocol is X configured to use with your mouse? You might try
DM> specifying "ExplorerPS/2" instead, and seeing if that helps.

It was just "PS/2".  "ExplorerPS/2" didn't seem to help.

DM> The solution I resorted to, back when I grappled with this problem,
DM> was to take the plunge and switch to USB input devices, in conjunction
DM> with a USB KVM switch. (I think that X didn't support the Explorer
DM> protocol back then, so something that effectively dis- and reconnected
DM> the mouse every time one switched between computers was actually the
DM> most expedient solution.)

Can you do that with a 2.2 kernel?  Sounds nice, although I must say
that I was looking for an easier solution.

DM> You may also find the following links helpful as you tweak your
DM> mouse-related configuration.

DM>     http://www.freebsddiary.org/usb-mouse.php
DM>     http://www.deadman.org/X/xbuttons.html
DM>     http://xfree86.org/4.2.0/mouse.html

I'll check em out.  Thanks for the links.

Hey, for anyone else that has this problem, I neglected to mention
this workaround that I had forgotten about until just now:

When you switch into Linux and your mouse goes nuts, hit ctrl-alt-F8,
then ctrl-alt-F7.  Works for me.  Inelegant and annoying, but I think
it might beat 3 mice on the desk.

- josh

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