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Date: Sun, 22 Oct 1995 17:48:44 +1000
From: Bruce Evans <bde@zeta.org.au>
Message-Id: <199510220748.RAA26210@godzilla.zeta.org.au>
To: current@freebsd.org, fredriks@mcs.com
Subject: Re: ordering of isa_devtab_tty important?
Sender: owner-current@freebsd.org
Precedence: bulk

>What I found was that I had configured the mse device on the line above
>the sc device which in turn made the mse device the first entry in the
>isa_devtab_tty[] table. When I switched the two lines, the kernel came
>up just fine.

>So the question is what is the NEW assumption made about the first 
>isa_devtab_tty[] entry. I figure it might have something to do with
>the serial console stuff(I don't have it enabled). I'll keep looking
>to see if I can't pinpoint the problem further.

The support for syscons and pcvt in the same kernel broke it :(.
find_display() in isa.c requires display devices to be before serial
devices, not to mention before devices in isa_devtab_tty that aren't
really ttys.  It could abuse the `sensitive_hw' flag to select the
display devices.  Display devices aren't sensitive, but the sensitive_hw
flag is set for them so that they get probed early so that they don't
appear to be used before they are detected.

>Just for your information. The symptom of my non-booting kernel was that
>as soon as the cart-wheel stopped spinning, my modem lights would indicate
>TX/RX, my floppy would start to twirl and the hard drives would be accessed
>a couple of times. Some time the screen would go black and the come back
>as it normally does, however you never saw the version[] getting printed
>nor any of the device probe messages.

This happens because sio0 becomes the console.  You should get a login
prompt if the boot succeeds and you wait a little longer.

Bruce