[ltp] T42 in dock w/ KVM - mouse malfunction?

[James Knott]

Donald B. Altman wrote:
> 
> Hello,
> 
> I've got a new, lovely T42p and a Thinkpad mini-dock.  This is to replace my former
> Thinkpad A21p in a Thinkpad Dock.
> 
> I use the set-up with a Linksys KVM switch.  Using the old Thinkpad and dock, all works fine.
> Using the new T42p and Thinkpad mini-dock the mouse is flaky.  Basically, it freezes if I 
> switch away form the Thinkpad and then back to it (and a bunch of other situations).
> If I use a separate mouse plugged directly into the mini-dock, then all works fine (i.e.
> the keyboard and Video switch properly.)
> 
> I've tried a Belkin KVM, both with and without power supply and gotten the same behavior.
> I've swapped cables and gotten the same behavior.  I've confirmed that the old Thinkpad
> and dock still work properly using the same KVM hardware.
> I've tried the setup using a Thinkpad Dock II rather than a mini-dock with the same result.
> 
> IBM service claims they have never heard any report of a flaky mouse using a KVM switch
> with a Thinkpad.  they've also said they won't touch the problem since IBM doesn't sell a KVM.
> A Google search suggests others have encountered the problem, but I found nothing definitive.
> 
> Has anyone encountered a similar problem?  Has anyone found a solution?

Linux often has that problem, if Z-axis is enabled.  With the 2.4 
kernel, I can clear the problem by switching to a text console and then 
back to the desktop.  However, that fix doesn't seem to work with the 
2.6 kernel.  I would have thought that with all the people complaining 
about this, someone would have taken a look at the problem and fixed it 
by now.  It's been around for years.

I have this problem on a desktop system, so it's not just your ThinkPad. 
  Also, I've been using KVMs for years, and never seen this problem in 
Windows or OS/2.  What is it about Linux, that's causing the problem.