Re: [alsa-devel] [RFC/PATCH v6 03/12] media: Entities, pads and links

From: Clemens Ladisch
Date: Tue Dec 14 2010 - 10:30:49 EST


Laurent Pinchart wrote:
> On Tuesday 14 December 2010 14:31:55 Clemens Ladisch wrote:
> > Laurent Pinchart wrote:
> > > On Monday 13 December 2010 17:10:51 Clemens Ladisch wrote:
> > >> EXT_SPEAKER also includes headphones; there might be made a case for
> > >> having those as a separate subtype.
> > >
> > > Shouldn't headphones be represented by an EXT_JACK_ANALOG ?
> >
> > Headphone jacks are jacks; there are also USB headphones.
>
> So EXT_SPEAKER are speakers not connected through a jack (USB, internal
> analog, ...) ?

Yes.

When there is jack, the driver often does not know what is connected.

> > >> EXT_BROADCAST represents devices like TV tuners, satellite receivers,
> > >> cable tuners, or radios.
> > >
> > > There's clearly an overlap with V4L here.
> >
> > These come from the USB audio spec. Video devices are indeed likely to
> > be more detailed than just a single audio source. :)
>
> Does EXT_BROADCAST represent the TV tuner (or satellite receiver, cable tuner,
> radio tuner, ...) itself, or the connection between the tuner and the rest of
> the device ? Most TV tuner are currently handled by V4L2 and would thus turn
> up as V4L2 subdevs (I'm not sure if that's what we want in the long term, but
> it's at least the current situation).

>From the point of view of an audio device, this would be just some audio
source, much like a connector. We don't need this if there is some
better V4L entitity that the USB audio entity can be mapped to.


Regards,
Clemens
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