Sunblade 2000 hangs hard, related to X

[Kent West <westk@acu.edu>]

I have four SunBlade 2000s running Debian sid. For the most part they 
work great, but if the "wrong" key(s) are pressed, the machine hangs 
hard, so that the CAPS lock/Numlock indicators don't work, and the 
machine can no longer be pinged or ssh'd into. Power cycling is the only 
recourse available.

If at kdm's login screen, I press Ctrl-Alt-F8 to go to the second X 
session, things are fine IF there's a second X session on -F8; if not, 
the machine hangs.
If from a VT (say, Alt-F2), I press Alt-F8 to go to the second X 
session, things are fine IF there's a second X session on -F8; if not, 
the machine hangs.

If from anywhere, I press Stop-A, the machine hangs. If' I'm at a VT, I 
see the message "Type 'go' to resume   ok", but "go" doesn't do 
anything; the machine's totally hung. This happens even if I shut down 
kdm first.

There may be other keystrokes that hang the machine also, but these are 
duplicatable, every time.

Any clues?

Thanks!

--
Kent