Date: Mon, 21 Jul 1997 12:04:22 +0200 (MET DST) From: Luigi Rizzo <luigi@labinfo.iet.unipi.it> To: msmith@atrad.adelaide.edu.au (Michael Smith) Cc: msmith@atrad.adelaide.edu.au, multimedia@FreeBSD.ORG, hackers@FreeBSD.ORG Subject: Re: sound driver structure and configuration Message-ID: <199707211004.MAA20937@labinfo.iet.unipi.it> In-Reply-To: <199707210751.RAA22242@genesis.atrad.adelaide.edu.au> from "Michael Smith" at Jul 21, 97 05:21:11 pm
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> Luigi Rizzo stands accused of saying:
> > > Aha. May I offer a suggestion?
> > >
> > > Have the 'snd' controller pull in all the modules for the various
> > > on-card subsystems. Have each of these subsystems register themselves
> > > in a linker set using a 'name' field to identify themselves.
> > >
> > > Then have 'device at ...?' statements which pull in probe code for
> >
> > right, but this brings me back to the initial question. What does the
> > config progrm do when it finds a "device at foo?" statement ? I have
> > tried running config with different config files where foo is replaced
> > by bar o rother strings and see no difference in the output . I guess
> > the "isa" keyword is somehow magic (or it becomes specially treated
> > because of something in the "files.i386" file ?
>
> Oops, my previous wasn't good enough, sorry.
>
> The 'device at foo?' doesn't appear to do anything special, and my
> suggesting it was really wrong.
>
> Here, in full glory :
>
> controller snd? # sound support, also all chipset modules
>
> device zw0 at isa? port... # ZongleWonker ISA board probe
> ...
> device bf0 # Bafwangg PCI soundcard probe
>
>
> Then a chipset module might say :
>
> struct snddriver_module foo_codec = {
> foocodec_attach,
> SNDD_TYPE_CODEC,
> (void *)foocodec_function_switch,
> "foo_codec"
> }
> DATA_SET(snddriver, foo_codec);
...
> Does that make more sense? 8)
well, this is exactly what I have done! One minor difference, I have
used a "struct pnp_device" as follows:
static struct pnp_device cs4236 = {
"cs4236",
cs4236_probe,
cs4236_attach,
&cs4236_count,
NULL, /* shutdown */
&tty_imask /* imask */
};
so that I can easily use a different imask when needed.
Maybe I will need more fields in the struct pnp_device to make the
mechanism more flexible for other device types.
In fact the structure should be the same for ISA/PnP and PCI device,
but I understand that support for autoconfiguring devices
has been added according to the needs of specific buses and the
mechanism is not as clean as it might be. When I am done with the PnP
stuff I will talk back to those who implemented the pci things to
discuss this item.
Cheers
Luigi
-----------------------------+--------------------------------------
Luigi Rizzo | Dip. di Ingegneria dell'Informazione
email: luigi@iet.unipi.it | Universita' di Pisa
tel: +39-50-568533 | via Diotisalvi 2, 56126 PISA (Italy)
fax: +39-50-568522 | http://www.iet.unipi.it/~luigi/
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