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

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Message-ID: <87sgcbwcnf.wl-kuninori.morimoto.gx@renesas.com>
Date:   25 Aug 2020 13:54:28 +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

>             +static bool soc_component_is_pcm(struct snd_soc_dai_link_component *dlc)
>             +{
>             +     struct snd_soc_dai *dai = snd_soc_find_dai(dlc);
>             +
>             +     if (dai && (dai->component->driver->pcm_construct ||
>             +                 dai->driver->pcm_new))
>             +             return true;
>             +
>             +     return false;
>             +}
(snip)
> I tried testing this with LOCKDEP config enabled at my end.
> It seems I don't see warning originated from above function.
> Are you suggesting that, in general, snd_soc_find_dai()
> should be called with client_mutex held?

Hmm ? strange...

snd_soc_find_dai() is using lockdep_assert_held()

	struct snd_soc_dai *snd_soc_find_dai(...)
	{
		...
=>		lockdep_assert_held(&client_mutex);
		...
	}

and lockdep_assert_held() will indicate WARN_ON()

	-- lockdep.h --
	...
	#ifdef CONFIG_LOCKDEP
	...
	#define lockdep_assert_held(l)	do {				\
=>			WARN_ON(debug_locks && !lockdep_is_held(l));	\
		} while (0)

> May be snd_soc_dai_link_set_capabilities() requires similar fix?

Yes, I'm posting fixup patch.

	https://patchwork.kernel.org/patch/11719919/

Thank you for your help !!

Best regards
---
Kuninori Morimoto