Date: Thu, 11 Sep 1997 17:27:47 +1000 From: Mike Smith <mike@smith.net.au> To: Luigi Rizzo <luigi@labinfo.iet.unipi.it> Cc: mike@smith.net.au (Mike Smith), gurney_j@resnet.uoregon.edu, perhaps@yes.no, freebsd-hackers@freebsd.org Subject: Re: PnP support Message-ID: <199709110727.RAA07246@word.smith.net.au> In-Reply-To: Your message of "Thu, 11 Sep 1997 07:13:32 %2B0200." <199709110513.HAA23558@labinfo.iet.unipi.it>
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> > Please, if you are going to do this, go back to the discussion that
> > came up last time on this topic, most particularly the allocation and
> > attachment strategy that Stefan and I discussed. Doing this job
> > half-assed is just going to mean that it will have to be done again.
>
> where was it discussed ? I do not remember having seen this on
> -hackers, although I brought up the subject in july (specifically about
> the attach returning or not an error value) when I started working on
> PnP.
Ironically, I found most of my record of this thread in a folder with
your name on it. 8)
The most recent evocation was on -hackers under the titles
"sound driver structure and configuration" and
"Advice sought on PnP configuration"
The most succinct extract I have on the "new" model reads :
---8<---snip---8<---
- gather all the information :
PCI probe
PnP probe
get ISA config (compiled in, datafile, etc.)
get PCI/PnP identifier tables (compiled in, bootloader, etc.)
- attach PCI devices
I/O ports and IRQs are assigned by the PCI rules.
- attach PnP devices
IRQs are taken from the free pool left after PCI assignment and
those marked for 'legacy' use. I/O ports are probed as per the
PnP spec.
- walk ISA config data, probe possible devices
We know which IRQ and I/O resources are still available,
we can hunt for devices that match the gaps.
I think it's important to leave the 'legacy' devices until _last_, as
this prevents a PnP device being accidentally recognised as a 'legacy'
device.
---8<---snip---8<---
This was generally accepted (I think Stefan had a few claraifications
on it) as being the "most effective" way of going about it.
See also the thread "Backwards compatibiliy for isa_driver" on -current
around mid-May for Doug R's work, which should definitely be taken
seriously.
> I am asking because I would like to help on this.
I realise, and your work to data alone has been greatly appreciated;
don't make the mistake of thinking I'm trying to put it down!
mike
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