Re: RFC: Appropriate device detection for Wine (more advice needed)

[Takashi Iwai <tiwai@suse.de>]

At Mon, 13 Jun 2005 09:00:22 -0500,
Jeremy White wrote:
> 
> > I'd recommend to list up only the card names, and try to use either
> > "default:X" or "plughw:X" (the former is preferred, but not available
> > in the older version).
> 
> Wait; I worry that I misunderstand the use of 'default'.
> 
> Is there a thread or FM I should go read to fully understand?
> 
> That is, my understanding is that the default key is used
> so that an end user just tells his or her sound app
> to write to a 'defaults' device, and then Alsa worries
> about mapping that to the correct device.
> 
> However, in the case of Wine, my fundamental mission
> at initialization time is to provide a credible and
> useful list of sound devices back to the application,
> so the application can pick.  (At the same time, I need
> to report which of those choices is the default, and
> report that back to the application as well; I try to
> do that via the alsa config apis).

That's why I wrote above.  Just give the list of sound cards with
proper names, and let user choose the card, instead of the whole
device lists.

> But my first misunderstanding was that I thought there
> was just one default device, not one that can be
> iterated per card.  Does default:X simply get mapped
> to one of either 'hw:X' or 'plughw:X' (or whatnot) based
> on user preference?

Yes.  It's a new feature introduced since ALSA 1.0.8 (or 7?).
You can pass the card number to the "default" PCM.
Also, default:X automatically introduces the dmix for many hardwares
without multi-playback capability, while plughw doesn't.
This works unless user redefines the default in his ~/.asoundrc.

Using the word "default" is a bit tricky, I admit.
I originally wanted to name a different one, but we didn't conclude.


Takashi


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