i386/100831: sio ignores BIOS information about serial ports - bounty offered

[Jo Rhett]

The following reply was made to PR i386/100831; it has been noted by GNATS.

From: Jo Rhett <jrhett at svcolo.com>
To: Bruce Evans <bde at zeta.org.au>
Cc: freebsd-gnats-submit at freebsd.org, freebsd-i386 at freebsd.org,
        njl at freebsd.org
Subject: Re: i386/100831: sio ignores BIOS information about serial ports - bounty offered
Date: Fri, 4 Aug 2006 11:29:12 -0700

 On Aug 4, 2006, at 5:29 AM, Bruce Evans wrote:
 > It makes perfects sense when you understand that the unit number  
 > may be
 > assigned at many levels, starting with the BIOS.  Whether you can make
 > COM1 be COM2 at the BIOS level depends on BIOS support for this.  I've
 
 Sorry, saying nonsense like this confuses the issue.  COM1 is a CPM/ 
 DOS designation that means 0x3f8 irq 4.
 
 Saying COM1 = COM2 means "IO 0x3f8 irq 4 == 0x2f8 irq 3".  Can you  
 understand that this makes no sense?
 
 Physical port ordering has no meaning with regards to COM1 ports.   
 Even on the original IBM hardware you could set jumpers and swap  
 which physical port was COM1 and which was COM2.  I spent years doing  
 this! :-)
 
 -- 
 Jo Rhett
 senior geek
 Silicon Valley Colocation