🚀 go-pugleaf

rk@lexicon.com (Bob Kukura) writes:

>We have a Telebit T2500 connected via a built-in serial port at 19200
>baud with hardware flow control to a SPARCstation 2 running SunOS
>4.1.1b.

>Every day or two, it gets into a state where it won't answer the phone
>on incoming calls although outgoing calls work fine.  Usually the
>modem's DTR light is on, but in this state, it is off except during
>outgoing calls.

>Sometimes, killing the getty on the port fixes the problem, but
>usually the DTR light stays out and init refuses to start a new getty.

>Telebit technical support is not able to help, and the people we get
>our system support through claim that Suns don't do shared
>dialin/dialout modems.

I swear that I am going to get cron to post this every two weeks.  It seems
like that is how often I send out this answer.  Maybe I should make it
a FAQ for news.answers.  :-)

BTW, I have two 2500's on a Sun 3/50 that are very happy now doing shared
dialin/dialout.

I mailed this to the original poster, but will post it for everyone else.

***

This fix causes the kernel to wait longer to turn on DTR.  This gives
the T2500 more time to reset, it sometimes takes a while to recover
from a PEP connection.

My thanks to Erik J. Murrey (ejm@riscit.NOC.Vitalink.COM) and Dean
Long (dlong@oak.ucsc.edu) for putting the original fix on the net.

The original authors used 5 seconds, I've changed it to 6 as I found
that eliminated all problems on my 3/50.

I've added the patch to the systems file so that subsequent kernel
builds are correct.

I've only tested this on a Sun 3/50, but have suggested this to others
with Sun 4's and have not heard any negative results.  If you try this
with a Sun 4 I would appreciate hearing about it.

This patches the running kernel and /vmunix.  Comments are in parenthesis.

Patch:
# adb -w -k /vmunix /dev/mem
zsadtrlow/W 6		(patch running kernel)
zsadtrlow?W 6		(patch /vmunix)
$q

---

I figured out how to patch the file that generates the kernel when I 
do a new config, so that I wouldn't have to go in with adb after each
new config.  I assume if you have something other than a sun3, you 
cd to the appropriate directory under /sys.

Patch:
# cd /sys/sun3/OBJ
# adb -w zs_async.o
zsadtrlow?W 6
$q

-- 
John Harkin   +1 415 472-2452   moon!jh   uunet!nbn!jh   jh@nbn.com
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