New-bus unit wiring via hints..

[Peter Wemm]

On Thursday 11 October 2007, Marcel Moolenaar wrote:
> On Oct 11, 2007, at 2:41 PM, John Baldwin wrote:
> > 2) One of the things this fixes that is visible to users is that if
> > your
> >    machine gets the COM ports backwards when using ACPI it should
> > now get
> >    them correct (COM1 as sio0) assuming your COM ports use the
> > default hints
> >    and you have the default sio hints in your /boot/device.hints
> > file.
>
> I think you just pointed out the problem of using hints to wire
> down unit numbers, because hints will stop hinting and will start
> dictating. If I swap the serial ports in the BIOS then surely
> my hints will be wrong and ACPI will be right.

Not necessarily.  It has been a long standing problem that ACPI is wrong 
(or sub-optimal) about serial ports.  There are many machines that list 
0x2f8 first, and 0x3f8 second.  As a result, we bind sio0 to com2, and 
sio1 to com1.

I like the way John did it.  It reserves the unit numbers for hardware 
that matches the hints.  For example, sio0 may be reserved for a com 
port that is found that had 0x3f8.  If nothing has 0x3f8, then sio0 
won't be created.

> A default hints 
> file will be even more disastrous than before.



-- 
Peter Wemm - peter at wemm.org; peter at FreeBSD.org; peter at yahoo-inc.com
"All of this is for nothing if we don't go to the stars" - JMS/B5