kevin@msa3b.UUCP (Kevin P. Kleinfelter) (01/09/91)
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!)robin@batcomp.austin.ibm.com (Robin D. Wilson) (01/11/91)
In article <1489@msa3b.UUCP> kevin@msa3b.UUCP (Kevin P. Kleinfelter) writes: )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. Well,... There are really 2 problems here: 1) getty will not say "login:" unless it detects carrier on the tty. If there is a carrier signal present then the modem SHOULD be connected, OR the modem has carrier strapped high. DON'T STRAP CARRIER HIGH ON THE MODEM!!!!! 2) If the port is marked "BAD" by AIX, it is because you were generating bad logins OR there were too many tty overruns (interupts). If you turn off the modem, and then disable the port, this should allow the port to be cleared. As long as AIX sees CD, DSR, RTS/CTS, etc. coming from the device on the tty, it will leave it marked BAD. )Deleting and recreating the /dev/tty? does not fix the problem. You will still need to remove the offending signals, this is a "feature". -- +-----------------------------------------------------------------------------+ |The views expressed herein, are the sole responsibility of the typist at hand| +-----------------------------------------------------------------------------+ |UUCP: robin%aixserv@uunet.uu.net | |USNail: 701 Canyon Bend Dr. | | Pflugerville, TX 78660 | | Home: (512)251-6889 Work: (512)823-3015 | +-----------------------------------------------------------------------------+