disabling all serial input / output at boot time

Bernd Walter ticso at cicely7.cicely.de
Thu Apr 15 19:28:48 UTC 2010


On Thu, Apr 15, 2010 at 09:25:24PM +0200, Bernd Walter wrote:
> On Thu, Apr 15, 2010 at 09:04:05PM +0200, Bernd Walter wrote:
> > 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.
> 
> Ups - I  ment boot2 and not boot0 - you likely don't install boot0.

For boot2 take a look into sys/boot/i386/boot2/boot2.c xgetc function.
I assume it is all you need to chnage.
> 
> > 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 at bwct.de> http://www.bwct.de
> > Modbus/TCP Ethernet I/O Baugruppen, ARM basierte FreeBSD Rechner uvm.
> > _______________________________________________
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> 
> -- 
> B.Walter <bernd at bwct.de> http://www.bwct.de
> Modbus/TCP Ethernet I/O Baugruppen, ARM basierte FreeBSD Rechner uvm.
> _______________________________________________
> freebsd-hackers at freebsd.org mailing list
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-- 
B.Walter <bernd at bwct.de> http://www.bwct.de
Modbus/TCP Ethernet I/O Baugruppen, ARM basierte FreeBSD Rechner uvm.


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