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

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Message-ID: <94e2c4ad-91a8-76c8-c956-8dbfdf68d1a8@nvidia.com>
Date:   Tue, 18 Aug 2020 13:36:37 +0530
From:   Sameer Pujar <spujar@...dia.com>
To:     Kuninori Morimoto <kuninori.morimoto.gx@...esas.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 Kuninori,

On 8/18/2020 8:11 AM, Kuninori Morimoto wrote:
> External email: Use caution opening links or attachments
>
>
> 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;

OK. I will keep the additional check. Thanks.

>
> Thank you for your help !!
>
> Best regards
> ---
> Kuninori Morimoto