Re: [PATCH v2 3/9] ASoC: audio-graph: Identify 'no_pcm' DAI links for DPCM

From: Kuninori Morimoto
Date: Mon Aug 17 2020 - 22:42:01 EST



Hi Sameer

> PCM devices are created for FE dai links with 'no-pcm' flag as '0'.
> Such DAI links have CPU component which implement either pcm_construct()
> or pcm_new() at component or dai level respectively. Based on this,
> current patch exposes a helper function to identify such components
> and populate 'no_pcm' flag for DPCM DAI link.
>
> This helps to have BE<->BE component links where PCM devices need
> not be created for CPU component involved in such links.
>
> Signed-off-by: Sameer Pujar <spujar@xxxxxxxxxx>
> ---
(snip)
> @@ -259,6 +270,16 @@ static int graph_dai_link_of_dpcm(struct asoc_simple_priv *priv,
> if (ret < 0)
> goto out_put_node;
>
> + /*
> + * In BE<->BE connections it is not required to create
> + * PCM devices at CPU end of the dai link and thus 'no_pcm'
> + * flag needs to be set. It is useful when there are many
> + * BE components and some of these have to be connected to
> + * form a valid audio path.
> + */
> + if (!soc_component_is_pcm(cpus))
> + dai_link->no_pcm = 1;
> +

For safety, I want to judge with data->component_chaining.

if (data->component_chaining &&
!soc_component_is_pcm(cpus))
dai_link->no_pcm = 1;

Thank you for your help !!

Best regards
---
Kuninori Morimoto