[alsa-devel] [PATCH v2 2/2] ASoC: adau17x1: Do not reload dsp-fw if samplerate has not changed

[Lars-Peter Clausen]

On 04/09/2018 03:13 PM, Robert Rosengren wrote:
> From: Danny Smith <dannys at axis.com>
> 
> Reloading fw causes an audiable popping sound, we can avoid this
> by not reloading if the samplerate is the same as before.
> 
> Signed-off-by: Danny Smith <dannys at axis.com>
> Signed-off-by: Robert Rosengren <robert.rosengren at axis.com>

Acked-by: Lars-Peter Clausen <lars at metafoo.de>

> ---
>  sound/soc/codecs/adau17x1.c | 9 +++++++++
>  1 file changed, 9 insertions(+)
> 
> diff --git a/sound/soc/codecs/adau17x1.c b/sound/soc/codecs/adau17x1.c
> index 12bf24c26818..ae41edd1c406 100644
> --- a/sound/soc/codecs/adau17x1.c
> +++ b/sound/soc/codecs/adau17x1.c
> @@ -843,6 +843,15 @@ int adau17x1_setup_firmware(struct snd_soc_component *component,
>  	struct adau *adau = snd_soc_component_get_drvdata(component);
>  	struct snd_soc_dapm_context *dapm = snd_soc_component_get_dapm(component);
>  
> +	/* Check if sample rate is the same as before. If it is there is no
> +	 * point in performing the below steps as the call to
> +	 * sigmadsp_setup(...) will return directly when it finds the sample
> +	 * rate to be the same as before. By checking this we can prevent an
> +	 * audiable popping noise which occours when toggling DSP_RUN.
> +	 */
> +	if (adau->sigmadsp->current_samplerate == rate)
> +		return 0;
> +
>  	snd_soc_dapm_mutex_lock(dapm);
>  
>  	ret = regmap_read(adau->regmap, ADAU17X1_DSP_SAMPLING_RATE, &dspsr);
>