[alsa-devel] [RFC] Channel mapping API

Takashi Iwai tiwai at suse.de
Tue Aug 21 19:09:32 CEST 2012

At Tue, 21 Aug 2012 17:34:15 +0100,
Mark Brown wrote:
> On Tue, Aug 21, 2012 at 05:38:28PM +0200, David Henningsson wrote:
> > On 08/21/2012 05:07 PM, Mark Brown wrote:
> > >Which of course is also replicated with the calls into the original
> > >jack API.
> > Actually, the phantom jacks are only in the ctljack API. I
> > deliberately left them out of the old jack API, because it was
> > deprecated (or at least so I thought).
> Like I say it seems like the wrong way round to do things - we've got a
> reasonable set of drivers using the jack API and a single driver using
> the ctljack API, with the ctljack API being very much a subset of the
> jack API (in that it only supports disconnected boolean values).  I
> still don't understand why it was ever implemented as a separate API.

The API itself doesn't restrict the boolean -- it's a control element
after all.

The reason for ctljack API was stated many times: it came because of
shortcomings of the jack API regarding the multiple items.  For
example, when multiple pins with the same type exist (e.g. typical for
HD-audio), no standard way to resolve that.  Or, if multiple cards
provide the same name of jacks, we don't know which device is for
which card.

But, it's basically irrelevant with the channel map API discussion.


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