linux-kernel - Re: [PATCH v3 1/2] ASoC: dt-bindings: sound-card-common: List DAPM endpoints ignoring system suspend

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Message-ID: <f639c88d-371a-4c72-a906-47d643b24ca8@sirena.org.uk>
Date:   Wed, 11 Oct 2023 22:21:33 +0100
From:   Mark Brown <broonie@...nel.org>
To:     Chancel Liu <chancel.liu@....com>
Cc:     lgirdwood@...il.com, robh+dt@...nel.org,
        krzysztof.kozlowski+dt@...aro.org, conor+dt@...nel.org,
        shengjiu.wang@...il.com, Xiubo.Lee@...il.com, festevam@...il.com,
        nicoleotsuka@...il.com, perex@...ex.cz, tiwai@...e.com,
        shawnguo@...nel.org, s.hauer@...gutronix.de, kernel@...gutronix.de,
        alsa-devel@...a-project.org, linux-kernel@...r.kernel.org,
        linuxppc-dev@...ts.ozlabs.org, devicetree@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH v3 1/2] ASoC: dt-bindings: sound-card-common: List DAPM
 endpoints ignoring system suspend

On Wed, Oct 11, 2023 at 07:47:58PM +0800, Chancel Liu wrote:

> +  lpa-widgets:
> +    $ref: /schemas/types.yaml#/definitions/non-unique-string-array
> +    description: |
> +      A list of DAPM endpoints which mark paths between these endpoints should
> +      not be disabled when system enters in suspend state. LPA means low power
> +      audio case. For example on asymmetric multiprocessor, there are Cortex-A

I suspect that the DT maintainers would prefer that this description be
workshopped a bit to remove the Linux specifics.  I think the key thing
here is that these are endpoints that can be active over suspend of the
main application processor that the current operating system is running
(system DT stuff is an interesting corner case here...), and the example
is probably a bit specific.  Other bindings use "audio sound widgets"
rather than "DAPM widgets".

We also shouldn't see that these endpoints "should not be disabled"
since that implies that they should be left on even if they aren't
active which isn't quite the case, instead it's that we can continue
playing an audio stream through them in suspend.

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