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From: newton@cleese.apana.org.au (Mark Newton)
Newsgroups: comp.os.386bsd.bugs
Subject: Re: PROBLEMS WITH FreeBSD
Date: 5 Jan 1994 19:40:44 +1030
Organization: cleese.apana.org.au public access UNIX +61-8-3736006
Lines: 48
Message-ID: <2ge072$d3q@cleese.apana.org.au>
References: <CIq8w7.7rM@csi.compuserve.com> <2g0kdl$2d9@cleese.apana.org.au> <2g2ere$esn@solaria.mil.wi.us>
NNTP-Posting-Host: cleese.apana.org.au
In article <2g2ere$esn@solaria.mil.wi.us> jgreco@solaria.sol.net (Joe Greco) writes:
>In comp.os.386bsd.bugs article <2g0kdl$2d9@cleese.apana.org.au>, newton@cleese.apana.org.au (Mark Newton) wrote:
>:If you did, and you still couldn't login, then the most likely reason is
>:that you have dumb 3-wire serial cable. The sio drivers behave like
>:"real" UNIX tty drivers -- they don't complete their open() until DCD is
>:asserted unless you disable that feature with ioctl() or tcsetaddr()
>:(or, from the shell, use "stty clocal").
>:
>:The sio drivers also know about flow control, so if you have 3-wire
>:null modems which don't have a clue about flow control, you'll have to
>:use stty -crtscts too. Note that getty will try to turn crtscts back
>:on (so disabling flow control then starting up getty is a pointless
>:exercise).
[ ... [
>
>Now wait a minute. I thought the SIO drivers were supposed to provide
>bidirectional capability. How is this supposed to work? I've been looking
>for documentation for about a week, and have yet to find anything.
Ah, yes. I didn't mention it in my previous article, largely due to
oversight caused by the fact that I don't use sio's bidirectional
capability in my kernel (in my configuration, life is very much simpler
without it).
You can enable bidirectionality by config'ing a kernel with
"options COM_BIDIR". Once that kernel is running, you can turn
bidirectionality on or off on an individual terminal basis with the
/sbin/comcontrol command. For example, "comcontrol /dev/tty00 bidir"
turns bidirectionality on for tty00, and "comcontrol /dev/tty00 -bidir"
turns it off.
>Under SunOS, which IMHO has a "reasonable" bidirectional mechanism, open()
sio works kinda like SunOS's. It apparently has some strange race conditions
associated with DCD transitions, but I can't comment on them 'cos I don't
run bidirectional terminals :-)
>Ideally, I'd _love_ to see this done with SIO, and I was actually under the
>impression that SIO had a direct analogy of some sort.
Si!
- mark
--
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I tried an internal modem, newton@cleese.apana.org.au
but it hurt when I walked. Mark Newton
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