[ltp] General Hardware Question - Mouse Problems with a KVM? (was Recommended... $1500)

[Alex Deucher]

On Mon, 31 Jan 2005 10:48:23 -0500, Donald B. Altman
<dona@singulartech.com> wrote:
> ** Reply to message from Bob Alexander <bob@ngi.it> on Mon, 31 Jan 2005 16:15:35 +0100
> 
> Bob,
> 
> Just a question re your T series and port replicator....
> 
> Have you ever had any mouse problems when using a KVM?
> 
> I have a T42p.  I hook it up through a KVM switch.  Using either a Thinkpad dock II
> or mini-dock (I never tried a port replicator) I can't get my PS2 mouse
> to work reliably.  It works reliably when I first boot.  Once I switch away from
> the T42p and back, though, it's locked up.  The keyboard switches with no problems.
> 
> This also happens using XP, so it's not  Linux problem, but rather one in  hardware.
> 
> I've swapped every hardware component in the chain after the T42p with no change.  Also,
> I used the same KVM hardware on my old A21p with Thinkpad dock and had no problems,
> so it's clearly a T42p and docking station problem.  (Since the T42p has no PS2
> ports, I have to use it in some sort of dock)
> 
> My current Kludgey workaround is to use a second mouse into a USB port of
> the Thinkpad mini-dock and use the KVM to switch the keyboard and monitor.
> 
> I've lived with this one for 5 months while lurking on this list, pinging IBM support,
> Googling, and everything I can think of.  If anyone has any insight to offer, I'd
> be very grateful.
> 
> TIA,
> 
> Don A
> 
> --
> Donald B. Altman
> Singular Technologies
> Croton-on-Hudson,  NY

Mice are notoriously bad with KVMs.  For me, PS/2 mice always cause
problems regardless of the kvm.   Work-arounds include switching to
another VT and back and unpluging and replugging the mouse patch
cable.  I remember seeing some patches for linux-input on LKML for
better handling of ps/2 devices with KVMs.  I'm not sure if they have
been merged upstream or not yet.

Alex