linux-kernel - Re: [PATCH v2 3/9] ASoC: audio-graph: Identify 'no

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Date:   18 Aug 2020 11:41:57 +0900
From:   Kuninori Morimoto <kuninori.morimoto.gx@...esas.com>
To:     Sameer Pujar <spujar@...dia.com>
Cc:     <broonie@...nel.org>, <perex@...ex.cz>, <tiwai@...e.com>,
        <robh+dt@...nel.org>, <lgirdwood@...il.com>,
        <thierry.reding@...il.com>, <jonathanh@...dia.com>,
        <alsa-devel@...a-project.org>, <linux-tegra@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <sharadg@...dia.com>,
        <mkumard@...dia.com>, <viswanathl@...dia.com>,
        <rlokhande@...dia.com>, <dramesh@...dia.com>,
        <atalambedu@...dia.com>, <nwartikar@...dia.com>,
        <swarren@...dia.com>, <nicoleotsuka@...il.com>
Subject: Re: [PATCH v2 3/9] ASoC: audio-graph: Identify 'no_pcm' DAI links for DPCM


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@...dia.com>
> ---
(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