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Date:      Mon, 19 Feb 1996 05:57:09 -0600 (CST)
From:      Kent Hamilton <kenth@HNS.St-Louis.Mo.US>
To:        freebsd-current@freebsd.org
Subject:   Re: Keyboard lockout on 2.x.x
Message-ID:  <199602191157.FAA00984@gwydion.hns.st-louis.mo.us>

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> 
> As Kent Hamilton wrote:
> > > 
> > > When exactly does it lock up?
> > 
> > Ohh, sorry, I've seen this mentioned here before so I guess I thought
> > it was a well known problem.  I'm using syscon and when flipping to a
> > different vt you'll get locked out.
> 
> Does this happen for all keyboards?  Does disconnecting/reconnecting
> the keyboard help?

No, that was the first thing I tried.  (Several times)

> 
> Keyboard lockup during VT switch is most likely due to a collision on
> the keyboard interface arising out of simultaneously sending a
> character code, while the driver is sending a SET LEDS command to the
> keyboard.

I remembered someone saying it had to do with the LED's, I have 
re-set the machines to not turn them on at boot and I almost never
use a caps/num lock anyway.  What else will toggle the LED states?
Scroll lock which I never use... anything else?

> 
> The keyboard serial interface hasn't been designed to be two-way, but
> later (for the PC/AT) been used for this.  Since you can rlogin into
> the machine, try compiling the kbdio(8) hacker's tool from
> /usr/src/usr.sbin/pcvt/kbdio, and see if you could also issue a
> keyboard reset.  Sorry, no man page, only the usage help (try -h).

Thanks I'll try that next time it happens and post a result.

Can anyone think of a good way to debug this one?  I don't mind doing
minor mucking with the code but I'm not a great C programmer.  (I'm
a sysadmin who used to be a FORTRAN/Assembler programmer many years
ago on PDP-11's/VAX's.)

I can cause this to happen pretty easily.  Just starting a 'make world'
in the source tree then fliping through the vt's quickly will do it.
Pretty annoying too when you've just started a compile and are 
flipping away and can't get back to see when it's completed.  I've 
taken to doing everything with 'make all >& /var/tmp/make.log &' at
least I can see what's going on remotely.  :-(

-- 
Kent Hamilton                               Work:  KHamilton@Hunter.COM
URL:  http://www.icon-stl.net/~khamilto     Play:  KentH@HNS.St-Louis.Mo.US



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