linux-kernel - Re: [PATCH] ASoC: soc-pcm: fix hw->formats cleared by soc_pcm_hw

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Message-ID: <875yb5frnl.wl-kuninori.morimoto.gx@renesas.com>
Date:   Sun, 12 Mar 2023 23:58:59 +0000
From:   Kuninori Morimoto <kuninori.morimoto.gx@...esas.com>
To:     Shengjiu Wang <shengjiu.wang@....com>
Cc:     shengjiu.wang@...il.com, lgirdwood@...il.com, broonie@...nel.org,
        perex@...ex.cz, tiwai@...e.com, alsa-devel@...a-project.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] ASoC: soc-pcm: fix hw->formats cleared by soc_pcm_hw_init() for dpcm


Hi Shengjiu

> The hw->formats may be set by snd_dmaengine_pcm_refine_runtime_hwparams()
> in component's startup()/open(), but soc_pcm_hw_init() will init
> hw->formats in dpcm_runtime_setup_fe() after component's startup()/open(),
> which causes the valuable hw->formats to be cleared.
> 
> So need to store the hw->formats before initialization, then restore
> it after initialization.
> 
> Signed-off-by: Shengjiu Wang <shengjiu.wang@....com>
> ---
>  sound/soc/soc-pcm.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/sound/soc/soc-pcm.c b/sound/soc/soc-pcm.c
> index 5eb056b942ce..7958c9defd49 100644
> --- a/sound/soc/soc-pcm.c
> +++ b/sound/soc/soc-pcm.c
> @@ -1661,10 +1661,14 @@ static void dpcm_runtime_setup_fe(struct snd_pcm_substream *substream)
>  	struct snd_pcm_hardware *hw = &runtime->hw;
>  	struct snd_soc_dai *dai;
>  	int stream = substream->stream;
> +	u64 formats = hw->formats;
>  	int i;
>  
>  	soc_pcm_hw_init(hw);
>  
> +	if (formats)
> +		hw->formats &= formats;
> +

If my understanding was correct, dpcm_runtime_setup_fe() (B) is called
after __soc_pcm_open() (A), and you updated (B) part.

	static int dpcm_fe_dai_startup(...) {
		...
(A)		ret = __soc_pcm_open(fe, fe_substream);
		...
(B)		dpcm_runtime_setup_fe(fe_substream);
		...
	}

But, it is doing same things under (A), too.
Do we need to initialize hw many times ? I'm not sure.
Can we simply remove soc_pcm_hw_init() from dpcm_runtime_setup_fe() ?

(A)	static int __soc_pcm_open()
	{
		...
(X)		soc_pcm_init_runtime_hw(substream);
		...
	}

(X)	static void soc_pcm_init_runtime_hw(...)
	{
=>		u64 formats = hw->formats;

(Y)		snd_soc_runtime_calc_hw(rtd, hw, substream->stream);

=>		if (formats)
=>			hw->formats &= formats;
	}

(Y)	int snd_soc_runtime_calc_hw(...)
	{
		...
=>		soc_pcm_hw_init(hw);
		...
	}

Thank you for your help !!

Best regards
---
Kuninori Morimoto