Date: Fri, 11 Jan 2002 20:25:29 -0500 From: Leo Bicknell <bicknell@ufp.org> To: Terry Lambert <tlambert2@mindspring.com> Cc: Lyndon Nerenberg <lyndon@atg.aciworldwide.com>, John Baldwin <jhb@FreeBSD.ORG>, freebsd-hackers@FreeBSD.ORG, Alfred Perlstein <bright@mu.org> Subject: Re: serial console + boot blip Message-ID: <20020112012529.GA47286@ussenterprise.ufp.org> In-Reply-To: <3C3F3E1D.F23F9BD7@mindspring.com> References: <bicknell@ufp.org> <20020111042439.GA24433@ussenterprise.ufp.org> <200201111648.g0BGmA2I047791@atg.aciworldwide.com> <20020111165416.GA36184@ussenterprise.ufp.org> <3C3F3E1D.F23F9BD7@mindspring.com>
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In a message written on Fri, Jan 11, 2002 at 11:33:49AM -0800, Terry Lambert wrote:
> I'm guessing that, even though you are not saying it, that the DTR
> drop occurs *immediately* after the probe and attach, and not some
> short time after the init scripts have fully rung, and the getty's
> are started, initiating "first opens" (this is an educated guess
> from looking at the code).
No, this is wrong. The probe comes and goes, and I see a long list
of probes after it. The drop is after the last kernel probe, and
before the first non-kernel message (verified for both single user
and multi-user now).
Again the best way I know to describe this is that the drop occurs
when the "boot sequence" switches from bold print to normal print
on a CRT. Hooking up a crt to the same spot, and comparing messages
with what I see on the serial port shows this is when it happens.
What I have now realized is that this is long before getty runs, since
it is not run on the console until the boot scripts complete.
I now suspect the bios is leaving DTR high, and when init sets up
stdout (for the rc scripts) and/or "opens the console" is when
DTR is momentarily dropped.
I'll be darned if I can see where that happens in init though.
--
Leo Bicknell - bicknell@ufp.org - CCIE 3440
PGP keys at http://www.ufp.org/~bicknell/
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