[alsa-devel] [PATCH v1 9/9] ASoC: Intel: Boards: add support for HDA codecs

[Takashi Iwai]

On Tue, 27 Feb 2018 17:20:05 +0100,
Ughreja, Rakesh A wrote:
> 
> >> The hdac_hda is just a wrapper around the legacy codec driver
> >> and so it relies on the functionality of the legacy HDA codec driver
> >> for all the functionality including pin re-tasking.
> >>
> >> The widget names that you see above is just to complete the
> >> DAPM route. Based on your comment I am planning to rename it as
> >> following
> >>
> >> Analog In Endpoint
> >> Analog Output Endpoint
> >> Digital In Endpoint
> >> Digital Out Endpoint
> >>
> >> and will connect it to the Codec Pins.
> >>
> >> Also I think it makes sense to rename the codec Pin names accordingly
> >>
> >> Codec Analog Input Pin
> >> Codec Analog Output Pin
> >> Codec Digital Input Pin
> >> Codec Digital Output Pin
> >
> >Humm, what if you have more than one analog input? It's almost as if
> >this list should be created dynamically based on what is exposed by the
> >codec, I don't see how a static list will cover all configurations.
> 
> If it is really required it can be done, the codec->pcm_list_head has got
> entries stored.
> 
> But I am not sure what is the behavior of the legacy HDA codec driver
> when it sees more than one Analog inputs.
> 
> Takashi, will I see two Analog entries in the pcm_list_head ?

Yes, in a few cases, the generic parser creates another PCM for analog
I/O as "Alt Analog":

- When a DAC is available for the headphone independently from others
  ("independent HP" stream)

- When there are multiple ADCs and neither dynamic ADC switch nor
  auto-mic selection feature is used


Takashi