Date: Fri, 21 Nov 2003 12:44:45 +0100
Message-ID: <s5hptfmx7wy.wl@alsa2.suse.de>
From: Takashi Iwai <tiwai@suse.de>
To: Adam Belay <ambx1@neo.rr.com>
Cc: arvidjaar@mail.ru, linux-kernel@vger.kernel.org, rusty@rustcorp.com.au,
       perex@suse.cz
Subject: Re: modules.pnpmap output support
In-Reply-To: <20031120212320.GB25417@neo.rr.com>
References: <s5hptfrjezz.wl@alsa2.suse.de>
	<E1ALky0-000N9I-00.arvidjaar-mail-ru@f25.mail.ru>
	<s5had6vj99t.wl@alsa2.suse.de>
	<20031120212320.GB25417@neo.rr.com>
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At Thu, 20 Nov 2003 21:23:20 +0000,
Adam Belay wrote:
> 
> On Mon, Nov 17, 2003 at 04:37:50PM +0100, Takashi Iwai wrote:
> > At Mon, 17 Nov 2003 18:07:04 +0300,
> > Andrey Borzenkov wrote:
> 
> -->snip
> 
> > > > the file2alias format of (isa) pnp devices will need variable number
> > > > of items, since a driver may require multiple ids.
> > > > for example, snd-cs4236 driver supports the cards with three ids like
> > > > 	CSCe825:CSC0100:CSC0110
> > > > and four ids like
> > > > 	CSCd937:CSC0000:CSC0010:CSC0003
> > > > in each case, a matching card must include all ids listed there.
> > > >
> > >
> > > do you mean that card will have to have all of these IDs to match?
> > >
> > > I can't get it reading sources. When driver matches card against
> > > card driver it is apparently using only main IDs, not logical
> > > device IDs:
> > >
> > > driver/pnp/card.c:match_card()
> > >
> > > static const struct pnp_card_device_id * match_card(struct pnp_card_driver * drv, struct pnp_card * card)
> > > {
> > >  	const struct pnp_card_device_id * drv_id = drv->id_table;
> > >  	while (*drv_id->id){
> > >  		if (compare_pnp_id(card->id,drv_id->id))
> > >  			return drv_id;
> > >  		drv_id++;
> > >  	}
> > >  	return NULL;
> > >  }
> > >
> > > where are drv_id->devs used?
> >
> > hmm, i thought it checks the device ids but apparently it's not.
> > IMO, this is a bug, because there are cards with the same card id but
> > different device ids. (e.g. sound/isa/cs423x/cs4236.c)
> > in the logic above, only the first matching entry is checked and it
> > results in the failure of probing.
> >
> > Adam, what do you think?
> >
> 
> The device ID is checked, but this checking occurs during the driver's
> probe function, when it calls pnp_request_card_device.  This is needed
> in order for us to properly deal with multidevice cards, especially in
> ALSA.

well, the probe callback of all ALSA isapnp drivers doesn't look for
the matching device ids.  that is, the callback trusts that the pnp
core passes the correct pnp_card_device_id, and it checks only the
devices listed on this id.  so, as mentioned above, if there are
multiple entries with the same card id but different device ids,
probing the second entry will fail, because match_card() returns the
first matching id.

>   If possibly, I'd like to see the devices in these cards be
> handled individually in 2.7 but note that doing so would require
> changes to some drivers and subsystems.  The current system works well
> for 2.6.
> 
> Because of these factors, and the fact that pnp_device_id is also used,
> I think that we have to include all of the IDs in the pnpidmap.  This
> would include both the card id and the individual device IDs on each
> card.  pnp_device_id can use the isapnp card device ids in addition to
> the ids reported by the pnpbios.

oh, can pnp_device_id be a card id, too, not only a device id?


Takashi
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