[alsa-devel] [PATCH] ASoC: fsl_audmix: Add spin lock to protect tdms

[Nicolin Chen]

On Wed, Nov 06, 2019 at 03:27:45PM +0800, Shengjiu Wang wrote:
> Audmix support two substream, When two substream start
> to run, the trigger function may be called by two substream
> in same time, that the priv->tdms may be updated wrongly.
> 
> The expected priv->tdms is 0x3, but sometimes the
> result is 0x2, or 0x1.

Feels like a bug fix to me, so  might be better to have a "Fixes"
line and CC stable tree?

Anyway, change looks good to me:

Acked-by: Nicolin Chen <nicoleotsuka at gmail.com>

Thanks

> Signed-off-by: Shengjiu Wang <shengjiu.wang at nxp.com>
> ---
>  sound/soc/fsl/fsl_audmix.c | 6 ++++++
>  sound/soc/fsl/fsl_audmix.h | 1 +
>  2 files changed, 7 insertions(+)
> 
> diff --git a/sound/soc/fsl/fsl_audmix.c b/sound/soc/fsl/fsl_audmix.c
> index c7e4e9757dce..a1db1bce330f 100644
> --- a/sound/soc/fsl/fsl_audmix.c
> +++ b/sound/soc/fsl/fsl_audmix.c
> @@ -286,6 +286,7 @@ static int fsl_audmix_dai_trigger(struct snd_pcm_substream *substream, int cmd,
>  				  struct snd_soc_dai *dai)
>  {
>  	struct fsl_audmix *priv = snd_soc_dai_get_drvdata(dai);
> +	unsigned long lock_flags;
>  
>  	/* Capture stream shall not be handled */
>  	if (substream->stream == SNDRV_PCM_STREAM_CAPTURE)
> @@ -295,12 +296,16 @@ static int fsl_audmix_dai_trigger(struct snd_pcm_substream *substream, int cmd,
>  	case SNDRV_PCM_TRIGGER_START:
>  	case SNDRV_PCM_TRIGGER_RESUME:
>  	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
> +		spin_lock_irqsave(&priv->lock, lock_flags);
>  		priv->tdms |= BIT(dai->driver->id);
> +		spin_unlock_irqrestore(&priv->lock, lock_flags);
>  		break;
>  	case SNDRV_PCM_TRIGGER_STOP:
>  	case SNDRV_PCM_TRIGGER_SUSPEND:
>  	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
> +		spin_lock_irqsave(&priv->lock, lock_flags);
>  		priv->tdms &= ~BIT(dai->driver->id);
> +		spin_unlock_irqrestore(&priv->lock, lock_flags);
>  		break;
>  	default:
>  		return -EINVAL;
> @@ -491,6 +496,7 @@ static int fsl_audmix_probe(struct platform_device *pdev)
>  		return PTR_ERR(priv->ipg_clk);
>  	}
>  
> +	spin_lock_init(&priv->lock);
>  	platform_set_drvdata(pdev, priv);
>  	pm_runtime_enable(dev);
>  
> diff --git a/sound/soc/fsl/fsl_audmix.h b/sound/soc/fsl/fsl_audmix.h
> index 7812ffec45c5..479f05695d53 100644
> --- a/sound/soc/fsl/fsl_audmix.h
> +++ b/sound/soc/fsl/fsl_audmix.h
> @@ -96,6 +96,7 @@ struct fsl_audmix {
>  	struct platform_device *pdev;
>  	struct regmap *regmap;
>  	struct clk *ipg_clk;
> +	spinlock_t lock; /* Protect tdms */
>  	u8 tdms;
>  };
>  
> -- 
> 2.21.0
>