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From: Terry Lambert <tlambert@primenet.com>
Message-Id: <199712190353.UAA02805@usr01.primenet.com>
Subject: Re: close() on a modem taking a long time?
To: rantapaa@uswest.net (Erik E Rantapaa)
Date: Fri, 19 Dec 1997 03:53:01 +0000 (GMT)
Cc: freebsd-hackers@FreeBSD.ORG
In-Reply-To: <Pine.BSF.3.91.971218203457.9226A-100000@tahiti.oss.uswest.net> from "Erik E Rantapaa" at Dec 18, 97 08:39:55 pm
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> I've been tracking down a problem we've been having with sendpage
> and it appears that close() on a serial line attached to a modem
> can sometimes take a long time (like 20 minutes or more).
> Can anyone think of a reason why this might be happening
> (and more importantly, how to get around it)?
> 
> (btw, this is with 2.2.5)

Close attemptsd to flush output, I believe.

This delay could occur if the modem has dropped RTS, if the DCD is
still active.  I believe the flush occursbefore the DTR drop to
reset the modem.

If the modem is internal, well, then you get what you deserve (internal
modems suck).

If it's external, try power cycling the modem and see if that fixes it;
if it does, it points the way toward a fix... probably modem configuration,
since a modem in command mode should not be asserting DCD and the driver
should ignore RTS if DCD is not asserted.  Alternately, it should assert
RTS if it's not asserting DCD.


					Terry Lambert
					terry@lambert.org
---
Any opinions in this posting are my own and not those of my present
or previous employers.