Re: ASoC: soc-pcm2.c ?

[Pierre-Louis Bossart <pierre-louis.bossart@linux.dev>]

On 2/3/26 07:27, Kuninori Morimoto wrote:
> So I will not care about detail things first (= sampling rate, channels,
> etc,...), but focus about graph / routing thinks. I think this is the
> main part for it.

If we truly want to support digital routing, then this information is very much needed.

The graph may include elements that are required to adjust between 'domains' or skipped.
For example if your ALSA PCM device is configured for 8kHz and your codec DAI only supports 48kHz an SRC-based path needs to be enabled. Conversely if the ALSA PCM device and codec DAI both operate at 48kHz then the SRC can be skipped completely and not even be represented in the graph.

In addition, even if the sampling rate/ch/resolution properties are added to the graph, the concept of propagating information to downstream processing may not fly in all cases. For example, a mixer will typically be configured at a fixed frequency. The mixer should not be reconfigured dynamically to account for changes in the streams that need to be mixed, it's these streams that need to be adjusted prior to mixing.

I personally really liked Lars' notion of 'domain' to define strict/well-defined boundaries connecting subgraphs.