SUMMARY: Serial chip or keyboard locks up system?

From: Steve Simmons (
Date: Sat Jan 09 1993 - 20:41:08 CST

I wrote:

>We've got a system locking up in an odd fashion, and before sending a
>component off for the wrong repair thought we'd check out to see if
>anyone else is having a similar problem.
>We have a SLC which periodically freezes up with respect to the
>keyboard and mouse. It's completely accessible from the outside, and
>all relevant processes show themselves in input wait state. An echo to
>/dev/console shows up properly.
>The system can only be reset by physically detaching and reattaching
>the keyboard. The system does not detect the detach, but does break
>back to the prom monitor on reattach of the keyboard. You can then
>continue with a `C' command.
>My guess is either bad keyboard or bad serial chip. Anybody had a similar
>problem and/or solution?

Responses came from:

Michael Assels <>
Pam Skillman <> (Ian MacPhedran)
Ike Stoddard <>
Mike Raffety <>
Geert Jan de Groot <>

Many thanks to all. The responses were suggestions, hints to look
other places, or requests for a summary. Unfortunately the suggestions
were contradictory, leading me to think there are a number of failures
which could cause the symptoms. We swapped the keyboard for one of our
spares, and the problem has not recurred. If it does, we'll try these

From: Pam Skillman <>

>You don't say if you are in X [[ we're in OW2 --scs ]] when this
>happens, but we have had similar problems with X11R5 and SUNOS 4.1.2
>(not sure if it happens with other releases) where the keyboard locks
>up, but everything else (remote access to the machine is fine). You
>can login to the machine and use the command 'kbd_mode -a' to clear the
>problem and unhang the keyboard. There are other options to this X
>command (kbd_mode) that may help. I'm not sure if this is your
>problem, but it's worth a try I guess. Good Luck!!

From: (Ian MacPhedran)

>This also happens when someone uses ^S (xoff) on the console - try using
>^Q (xon) and see what happens ...

Other ideas:

From: Geert Jan de Groot <>

>Probably keyboard. You can detach the mouse to check. Swap them with
>another machine?


>Hmmmm. Sometimes similar phenomena appear on my SS2. Is the xnews
>server hogging the CPU? Are you running OW3.0 (as I am) or SunView?
>I've had to telnet in over ethernet and kill "xnews -cubesize large"
>to get my entire console back. I suspect you've already ruled this
>out, but just in case, this was my $0.02 worth....

Nope, we can log into the system from outside and load is at zero.

From: Mike Raffety <>

>What you're doing is equivalent to hitting "break" on a server. Does
>L1-A work? I suspect it may ... What SunOS are you running?

No it doesn't -- we're getting no keyboard response at all. Running
SunOS 4.1.1.

From: Michael Assels <>

>We have the identical problem with an IPC. I'm sorry I can't give you the
>solution, but I can narrow it down: Exchanging the keyboard (type 4) with
>a keyboard from another IPC doesn't help. The problem remains on the same
>machine, so it's not the keyboard.

Worked for us, leading me to believe we're dealing with a different
failure mode.

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