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Date:      Thu, 15 Apr 2010 21:04:05 +0200
From:      Bernd Walter <ticso@cicely7.cicely.de>
To:        Mike Tancsa <mike@sentex.net>
Cc:        freebsd-hackers@freebsd.org, ticso@cicely.de
Subject:   Re: disabling all serial input / output at boot time
Message-ID:  <20100415190405.GC31933@cicely7.cicely.de>
In-Reply-To: <201004151745.o3FHjXI2077062@lava.sentex.ca>
References:  <201004141357.o3EDvuxt067902@lava.sentex.ca> <20100415173659.GB31933@cicely7.cicely.de> <201004151745.o3FHjXI2077062@lava.sentex.ca>

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On Thu, Apr 15, 2010 at 01:45:36PM -0400, Mike Tancsa wrote:
> At 01:36 PM 4/15/2010, Bernd Walter wrote:
> 
> >Is the sensor prohibiting the use of USB RS232 in any way?
> 
> Just our wallets :)  Extra cost to include it and the case would need 
> to change as well as its in an environment where it can get hit by water.

Ok - that's an understandable reason.

The unfortunate thing is that the bootcode reacts on buffered input
and the BIOS might already have buffered some bytes.
This has nothing to do with FreeBSDs knowledge about comconsole because
the BIOS translates it.
IIRC the Soekris BIOS has an option to disable the SIO support, maybe
your board has something similar.
Otherwise this means you need to disable the bootcode (including boot0)
to process any kind of input.
This shouldn't be too hard to code since the code is well documented.
It happens in at least boot0 and loader - the later likely can be
handled by using a customized loader.rc script, which wraps to
nullconsole.

-- 
B.Walter <bernd@bwct.de> http://www.bwct.de
Modbus/TCP Ethernet I/O Baugruppen, ARM basierte FreeBSD Rechner uvm.



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