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Date:      Thu, 14 Sep 2000 07:53:19 -0600
From:      Joe.Warner@smed.com
To:        freebsd-hackers@freebsd.org
Cc:        RichardLe@pcmall.com
Subject:   /dev/cuaa0 locks my system up..Help!
Message-ID:  <8525695A.004C10AB.00@Deimos.smed.com>

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Ok, I'm posting this here as a last resort.  I've already done a search of
the freebsd mailing lists and have posted several times to
freebsd-questions but haven't received any information that has helped me
resolve this problem.

A while back, while trying to get my APC Smart-UPS 1000 to talk to my
FreeBSD 3.4 system, I encountered a problem with the serial port.  This
problem inspired my to write an article that was published at this months
edition of daemonnews.

http://www.daemonnews.org/200009/adventure.html

Regardless of what application I use to access my serial port (/dev/cuaa0),
when I do, it causes my system to freeze up.  CTRL + ALT + BACKSPACE
doesn't work, CTRL + ALT + F2 doesn't work,..you get the picture.  When my
system freezes like this, my only alternative is to do a cold reboot and I
don't think this is too healthy a practice for any OS.

After trying kermit to see if I can, at least, talk to the serial port, I
get the same results when trying to connect.  Someone suggested I also try
minicom but I couldn't get it installed.  It timed out when trying to
access the ftp sites listed in the Makefile.  I also tried to download and
install a newer version but couldn't get that to work either.  Possibly
because my ports need to be updated.

I've scoured the contents of all my logs and haven't found any error
message that would give a clue as to why this keeps happening.

The only thing I haven't tried is using a different serial cable.  The
folks at APC said they sell a specialized serial cable that's made to work
with UNIX systems.  I was about to purchase this cable and try it until I
received an email from a guy, in response to my article at daemonnews,
saying that he's experienced the exact same problem with his serial port as
well.  Even though he hasn't been trying to hook up a UPS but rather trying
to get his modem to dial.

My pc is a Compaq Deskpro 2000 (266mhz) with 64m RAM, running FreeBSD 3.4.
There is only one serial port on this pc.
There should be a way to find out why this keeps happening.  Even if I find
out that it's just not possible to get the serial port configured correctly
for a UPS, I'd still like to know why.

I've tried changing permissions for /dev/cuaa0 and the applications I've
used to access the port/device, I've tried using ps aux, top and fstat to
see if I can found out what process might be using the device but haven't
found anything tangible.

Even though it's not an emergency that I get this to work, it's a problem
I'd like to get fixed or at least find out why I'll never get it to work.
Any help would be greatly appreciated.

Thanks

Joe




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