[alsa-devel] RFC: ice1712 virtual devices

[Raymond Yau]

In the past when dmix is used , default device is defined in those .conf for
each card.

i.e. front device is not used for capturing.

e.g. emu10k1 has special hook for playback with the front device  and those
hook should not be used for capture.


2009/10/30 Arno Schuring <aelschuring at hotmail.com>

> Hello list,
>
> This is basically a resend of
> http://thread.gmane.org/gmane.linux.alsa.devel/59481/focus=59672 , which
>  fixed the front: device of ice1712 cards to accept two-channel input.
> Currently, the front: device is exposed through the route plugin, which
> requires all clients to mmap all 10 channels, even though the front
> device is supposed to be a stereo device.
>
> This patch changes the front: device definition such that it matches the
> definition of iec958 in the same file. Additionally, I'm tempted to
> remove the surround* definitions because the chip does not really offer
> surround-style multichannel: it basically just offers multiple stereo
> channels, and does not provide any channel mapping beyond stereo.
>
> Finally, I'm also experimenting with the dshare plugin to allow
> applications to access the iec958: and front: devices simultaneously.
> Can anyone point me to a working example for this? From reading the
> alsa-lib documentation, it is not clear to me how I should nest the
> different plugins.
>
>
> Many thanks,
> Arno Schuring
>
>
> --
>
> diff --git a/src/conf/cards/ICE1712.conf b/src/conf/cards/ICE1712.conf
> index 01e50d2..d7acb81 100644
> --- a/src/conf/cards/ICE1712.conf
> +++ b/src/conf/cards/ICE1712.conf
> @@ -32,12 +32,28 @@ ICE1712.pcm.front.0 {
>        @args.CARD {
>                type string
>        }
> -       type route
> -       ttable.0.0 1
> -       ttable.1.1 1
> -       slave.pcm {
> -               type hw
> -               card $CARD
> +       type asym
> +       playback.pcm {
> +               type route
> +               ttable.0.0 1
> +               ttable.1.1 1
> +               slave.pcm {
> +                       type hw
> +                       card $CARD
> +               }
> +               slave.format S32_LE
> +               slave.channels 10
> +       }
> +       capture.pcm {
> +               type route
> +               ttable.0.0 1
> +               ttable.1.1 1
> +               slave.pcm {
> +                       type hw
> +                       card $CARD
> +               }
> +               slave.format S32_LE
> +               slave.channels 12
>        }
>  }
>
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