[patch] simple sysfs sound objects

[Kay Sievers]

On Thu, 2005-02-10 at 13:46 -0500, David Zeuthen wrote:
> On Wed, 2005-02-09 at 21:41 +0000, Richard Hughes wrote:
> > Here is an simple initial patch to expose sound devices so you can see
> > what sound devices you've got on your system.
> > I'm not sure what do do with objects that don't have a physdev
> 
> Ignore such devices for now; AFAIK, all ALSA devices (the one we should
> care about) have such links. Otherwise they will get them eventually.
> 
> > , or how
> > it needs to be organised. Feel free to suggest ideas.
> > 
> > I've commented out the get_prober function, as I'm not sure what policy
> > should be.
> >
> > Comments please.
> 
> That's what you use when you need to get information about a device and
> that either requires
> 
>   - certain privileges
>   - retrieving the information may take a long time
> 
> I don't think this is needed for ALSA since everything appears to be
> in /proc/asound.
> 
> Regarding your patch, it looks like a good start; here are some things
> that I think is needed
> 
>  - patch against the spec documenting the various sound.* properties
>  - check that it's really an ALSA device and not a OSS device
>   - I think you can just look at the kernel name (the last element in
>     the sysfs path (check that it's starting with control or pcm, 
>     but note that ALSA might also expose things such as midi*)
>   - expose what kind of ALSA device it is; e.g. capture, playback,
>     control, midi whatever
>   - expose the name (look at /proc/asound/card%d/pcm%d[cp]/info)
>     and other information that may be useful

You may check for the "multimedia" capabilities we already use.
Video devices normally have audio channels too. So we may use the same
properties for "audio only" cards.

Thanks,
Kay

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