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

[Marcel Moolenaar]

On Aug 3, 2006, at 10:12 AM, Warner Losh wrote:

> The "minor logic" in newbus is actually kicking my ass right now.  I
> have stuff in p4 that should implement all the things we need, but the
> unit allocation is kicking my butt.  I fear that the only real way is
> to subclass isa three times: hints-only, pnp+hint-augment,
> acpi+hint-augment.  In the latter two, how does one tell a 'this hint
> is for a card that's there' versus a 'this hint is a wiring hint'?
> And for the wiring hints, how much of the device matching do you do?
> If the I/O matches, but the IRQ doesn't, is that a match?  What about
> vice versa?

Like I said before: hints are abused for way too many purposes.
It's better to come up with a new scheme where you clearly separate
the different functions we're looking for and design *as many*
different mechanisms to implement these functions.

One approach would be to make ACPI unconditional, as it's there
to describe the existence of legacy devices and thus serves the
same purpose as our current hints and define hints to *only*
allow wiring down hardware to unit numbers. These can be called
hints because I'm sure we can not always guarantee it.

Marking devices as special, like the sio flags is an entirely
different function alltogether and should therefore not be done
with the same hints. That would just create the convolution, so
you create different hints for that.

-- 
  Marcel Moolenaar         USPA: A-39004          marcel at xcllnt.net