Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!wuarchive!emory!rsiatl!nanovx!msa3b!kevin
From: kevin@msa3b.UUCP (Kevin P. Kleinfelter)
Newsgroups: comp.unix.aix
Subject: AIX 3 looses serial ports
Message-ID: <1489@msa3b.UUCP>
Date: 9 Jan 91 14:46:52 GMT
Organization: Dun and Bradstreet Software, Inc., Atlanta, GA
Lines: 30

YAASPP - Yet Another Aix Serial Port Problem

Our 6000 "looses" serial ports. We have 32 modems on the 64 port adapter.
Once the system decides there is a problem with a port, it will write to
it, but reads always act as if there is no data incoming.

For example, if we enable a port with a "smart" modem in echo mode,
AIX sends "login:" and the modem echos "login:" and AIX sends
"password:" and the modem echos "password" ad nauseum.  AIX cleverly
assumes that there is a problem with the port, and apparently marks it
as faulty.  From that point forward, all input from the port is
ignored.  The only fix I have found is to reboot.

Deleting and recreating the /dev/tty? does not fix the problem.
Killing the getty does not fix the problem.
Pdisable and penable does not fix the problem.

Note that the example I gave above is only one way to get AIX to
deactivate the port.  All of my modems are now programmed to not echo,
and I still loose occasional ports.

Two questions:

1. How can I reactivate the port without a reboot once the problem is fixed?
2. Other than my example above, what would make AIX tag the port as bad?
-- 
Kevin Kleinfelter @ Dun and Bradstreet Software, Inc (404) 239-2347
{emory,gatech}!nanovx!msa3b!kevin

Soon to become {emory,gatech}!nanovx!dbses0!kevin  (But not yet!)