Messages in this thread | | | Date | Mon, 13 Jan 2014 11:57:02 +0100 | From | Takashi Iwai <> | Subject | Re: [alsa-devel] [PATCH] ASoC: dpcm: don't do hw_param when BE has done hw_param |
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At Mon, 13 Jan 2014 10:48:51 +0000, Liam Girdwood wrote: > > On Sat, 2014-01-11 at 10:35 +0100, Takashi Iwai wrote: > > At Fri, 10 Jan 2014 18:43:09 +0000, > > Liam Girdwood wrote: > > > > > > On Fri, 2014-01-10 at 14:46 +0100, Takashi Iwai wrote: > > > > At Fri, 10 Jan 2014 12:29:08 +0000, > > > > Liam Girdwood wrote: > > > > > > > > > > > > The intention was to use the existing alsa-lib/tinyalsa PCM hw_params > > > APIs. The BE would just export itself to usespace as a PCM (but without > > > the capability for direct playback/capture - just format, rate setting) > > > > Does it mean that, from kernel perspective, a BE creates a dedicated > > (virtual) PCM device and expose it to user-space? Or just through > > special API? > > I'm thinking a virtual PCM if you agree. > > We could keep the same userspace API for configuration OR we could > extend the API slightly to add some snd_pcm_virtual_() functions. > Extending the API would imply the virtual PCM only supports a subset of > PCM API calls (avoiding any confusion/mixing with regular PCM APIs).
Yeah, I agree that a simple PCM device exposure would be more straightforward.
thanks,
Takashi
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