Re: DMIX and capture stream

[Takashi Iwai <tiwai@suse.de>]

At Wed, 07 Jan 2004 16:15:40 +0100,
Abramo Bagnara wrote:
> 
> Takashi Iwai wrote:
> > At Wed, 07 Jan 2004 15:39:14 +0100,
> > Abramo Bagnara wrote:
> > 
> >>
> >>I don't see your point, can you show me an example of what you mean?
> >>
> >>AFAICS the only code that need to be changed is the PCM definition lookup.
> > 
> > 
> > there are two parts to be modified, snd_pcm_open_noupdate() and
> > snd_pcm_slave_conf().  they are the parts which look up "pcm"
> > directive in the configuration.
> > the former is easy.  but the latter function doesn't have stream
> > argument, so it cannot check whether "pcmp" or "pcmc" to check.  and,
> > changing this function will need rewriting all callers...
> 
> I definitely don't see why you think snd_pcm_slave_conf need to be 
> changed. It does not need to know about pcmp/pcmc variants.
> 
> I'm missing something?

if i understand the code correctly, for defining a pcmp or pcmc as a
slave pcm, such as,

	pcm.foo {
		type plug
		slave {
			pcmp bar_playback
			pcmc bar_capture
		}
	}

snd_pcm_slave_conf() needs to know which one to be used, so that the
config subtree (of either pcmp, pcmc or pcm) is passed to
snd_pcm_open_slave().

otherwise, you have to define slave pcms always separetly, such as,

	pcm.foo {
		type plug
		slave {
			pcm bar
		}
	}
	pcmp.bar bar_playback
	pcmc.bar bar_capture

i think it's a big restriction.


Takashi


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