Re: [PATCH] ASoC: AM3517: Fix AIC23 suspend/resume hang

[Troy Kisky <troy.kisky@boundarydevices.com>]

Anuj Aggarwal wrote:
> System hang is observed While trying to do suspend. It was because
> of an infinite loop in the AIC23 resume path which was trying to
> restore AIC23 register values from the register cache.
> 
> This patch fixes the problem by correcting the resume path and
> properly activating/deactivating the digital interface while
> doing the suspend / off transitions.
> 
> Signed-off-by: Anuj Aggarwal <anuj.aggarwal@ti.com>
> ---
>  sound/soc/codecs/tlv320aic23.c |   16 +++-------------
>  1 files changed, 3 insertions(+), 13 deletions(-)
> 
> diff --git a/sound/soc/codecs/tlv320aic23.c b/sound/soc/codecs/tlv320aic23.c
> index 6b24d8b..cabe60c 100644
> --- a/sound/soc/codecs/tlv320aic23.c
> +++ b/sound/soc/codecs/tlv320aic23.c
> @@ -565,13 +565,12 @@ static int tlv320aic23_set_bias_level(struct snd_soc_codec *codec,
>  	case SND_SOC_BIAS_PREPARE:
>  		break;
>  	case SND_SOC_BIAS_STANDBY:
> -		/* everything off except vref/vmid, */
> -		tlv320aic23_write(codec, TLV320AIC23_PWR, reg | 0x0040);
> +		/* Activate the digital interface */
> +		tlv320aic23_write(codec, TLV320AIC23_ACTIVE, 0x1);
>  		break;
>  	case SND_SOC_BIAS_OFF:
> -		/* everything off, dac mute, inactive */
> +		/* Deactivate the digital interface */
>  		tlv320aic23_write(codec, TLV320AIC23_ACTIVE, 0x0);
> -		tlv320aic23_write(codec, TLV320AIC23_PWR, 0xffff);
>  		break;
>  	}
>  	codec->bias_level = level;
> @@ -615,7 +614,6 @@ static int tlv320aic23_suspend(struct platform_device *pdev,
>  	struct snd_soc_device *socdev = platform_get_drvdata(pdev);
>  	struct snd_soc_codec *codec = socdev->card->codec;
>  
> -	tlv320aic23_write(codec, TLV320AIC23_ACTIVE, 0x0);
>  	tlv320aic23_set_bias_level(codec, SND_SOC_BIAS_OFF);
>  
>  	return 0;
> @@ -625,14 +623,6 @@ static int tlv320aic23_resume(struct platform_device *pdev)
>  {
>  	struct snd_soc_device *socdev = platform_get_drvdata(pdev);
>  	struct snd_soc_codec *codec = socdev->card->codec;
> -	int i;
> -	u16 reg;
> -
> -	/* Sync reg_cache with the hardware */
> -	for (reg = 0; reg < ARRAY_SIZE(tlv320aic23_reg); i++) {
> -		u16 val = tlv320aic23_read_reg_cache(codec, reg);
> -		tlv320aic23_write(codec, reg, val);
> -	}

Changing to
	for (reg = 0; reg < ARRAY_SIZE(tlv320aic23_reg); reg++) {

should be enough to fix the infinite loop.
Could you try this without the rest of the patch?

>  
>  	tlv320aic23_set_bias_level(codec, SND_SOC_BIAS_STANDBY);
>  	tlv320aic23_set_bias_level(codec, codec->suspend_bias_level);

Adding Arun to cc list