Re: modules.pnpmap output support

[Takashi Iwai <tiwai@suse.de>]

At Sun, 23 Nov 2003 22:07:12 +0000,
Adam Belay wrote:
> 
> On Fri, Nov 21, 2003 at 12:44:45PM +0100, Takashi Iwai wrote:
> > At Thu, 20 Nov 2003 21:23:20 +0000,
> > Adam Belay wrote:
> 
> --> snip
> 
> > > 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.
> 
> Hmm, I agree, if there are multiple entries with the same card ID then
> only the first ID would be matched.  I could add some code to match_card()
> so that it checks to see if all of the devices in the list are present.
> This would, however, break ALSA's current policy of enabling a card, even
> if some of its device components are unavailabe.

this should be ok.  we already have multiple definitions for such a
case.

> Could you provide any
> specific examples of multiple entries with the same card ID?  I'd like to
> look at some closer.
 
sound/isa/cs423x/cs4236.c includes the following ids:

static struct pnp_card_device_id snd_cs423x_pnpids[] = {
	/* Intel Marlin Spike Motherboard - CS4235 */
	{ .id = "CSC0225", .devs = { { "CSC0000" }, { "CSC0010" }, { "CSC0003" } } },
	/* Intel Marlin Spike Motherboard (#2) - CS4235 */
	{ .id = "CSC0225", .devs = { { "CSC0100" }, { "CSC0110" }, { "CSC0103" } } },

also within the same list:

	/* Dell Optiplex GX1 - CS4236B */
	{ .id = "CSC6835", .devs = { { "CSC0000" }, { "CSC0010" }, { "CSC0003" } } },
	/* Dell P410 motherboard - CS4236B */
	{ .id = "CSC6835", .devs = { { "CSC0000" }, { "CSC0010" } } },

the latter is fallback for the board without MPU401. 

> > >   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?
> 
> Only a device ID, but those device IDs can reside on isapnp cards.

ok, that what i expected.


--
Takashi Iwai <tiwai@suse.de>		ALSA Developer - www.alsa-project.org