disabling all serial input / output at boot time

[Mike Tancsa]

At 12:18 PM 4/15/2010, Julian Elischer wrote:
>>>More of a workaround than a fix, but does it work any better
>>>if you connect the device to com2 instead of com1?
>>
>>
>>Unfortunately there is only one serial port on the board we are using.
>
>yes but can the bios map it to be com2?

The BIOS (Alix) is very "helpful" in that anything that boot0 (and I 
think boot2) prints out, it just puts it out the one serial port.  So 
even if I install boot0 and not boot0sio, I still get "stuff" on the 
one serial port. (Same with spinconsole from current) Similarly, I 
can compile a kernel sans uart and then load uart once things are 
fully booted. However, there is still output on the serial port 
(which I guess was destined for the console), so it does not seem to 
be an issue with FreeBSD's kernel as the input/output takes place 
prior to that.  I can disable serial output in the BIOS, but the 
problem is sometimes that gets factory reset in the field... Also, we 
are doing a few hundred of these things so invariably a few will be 
missed etc. So I would rather have an extra layer of protection to 
deal with it at the OS layer, not to mention I dont want any output 
that confuses the device I am to monitor.

         ---Mike
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ario Canada                       www.sentex.net/mike