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Date:      Mon, 27 Nov 95 10:14 WET
From:      uhclem%nemesis@fw.ast.com (Frank Durda IV)
To:        current@FreeBSD.org
Subject:   Re: Theory Failed: screen vs keyboard lock-up 
Message-ID:  <m0tK6Cl-0008mtC@nemesis.lonestar.org>

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[1]I can't tell you what's causing it but I've got similar symptoms
[1]since the beginnings.  Right now I'm running 2.1.0-SNAP-9507?? and
[1]it still happens every now and then.  The only thing I noticed is
[1]that it always happens when I switch screens during disk activity. 
[1]Also note that during a lockup I'm able to login on a serial line
[1]and everything works OK*.  It's only the console input which is lost
[1]until I reboot the machine.

I also came across this problem in 1.1.5.1 on keyboards made by Fujitsu
and others (all keyboards 8042-based).   If the system was particularly
busy on disk when I did a ALT-Fn screen change, about 10% of the time the
keyboard would appear to lock up. 

You could effectively cause the lockup to happen by rapidly changing
between screens that had updates occuring on them, such as "ls -alR /"
on a couple of screens, then toggle between them.

I also found that all I had to do was unplug and reconnect the keyboard
while the system was running and the keyboard would resume functioning. 
No need to reboot.

The problem completely disappeared for these keyboard brands (at
least on the systems I am responsible for) when I switched them over to
2.0.5-RELEASE.  Perhaps the timing was changed but not enough to cover
all keyboards, such as those using the "COPS" controller instead of a 8042.
(The "COPS" controller is a different processor used in some keyboards
 to avoid the fury of the Texas Instruments Patent Lawyers(TM) who
 have a patent on keyboard matrix scanning from the pocket calculator days.)

Try unplugging and reconnecting the keyboard and see if it "wakes up".

Frank Durda IV <uhclem@nemesis.lonestar.org>|"Knowledge is power, so be sure
or uhclem%nemesis@fw.ast.com (Fastest Route)| to give some away today.
...letni!rwsys!nemesis!uhclem               | Doing this annoys Microsoft."
...decvax!fw.ast.com!nemesis!uhclem         | (c) 1995 FDIV




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