KVM with 12.04

[Coll-Barth, Michael]

Folks,

I've been having some difficulty getting my TrendNet 4 port KVM box to
work with 12.04 on a Dell laptop.  I can see everything on the monitor
connected to the box from initialization to just before the login
screen.  I get a message about no signal and that's it.  

When I lift the laptop lid, I can work normally.  I've tried both Gnome
and KDE.
 
It worked perfectly well with 10.04.

There is no virtualization involved, which is what I've have been
dredging through in web searches.

Any ideas on what to check?  Where to check?  Need additional info?

Thanks,
mcb