Re: [PATCH] ASoC: q6apm-dai: schedule all the periods before we start streaming

[Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>]

On Mon, Feb 03, 2025 at 12:49:45PM +0000, srinivas.kandagatla@xxxxxxxxxx wrote:
> From: Srinivas Kandagatla <srinivas.kandagatla@xxxxxxxxxx>
> 
> With the existing code, we are only setting up one period at a time, in a
> ping-pong buffer style. This tiggers lot of underruns in the dsp
> leading to jitter noise during audio playback.
> 
> Fix this by scheduling all the periods, this will ensure that the dsp
> has enough buffer feed and ultimatley fixing the underruns and audio
> distortion.
> 
> Fixes: 9b4fe0f1cd79 ("ASoC: qdsp6: audioreach: add q6apm-dai support")
> Reported-by: Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxx>
> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@xxxxxxxxxx>
> ---
>  sound/soc/qcom/qdsp6/q6apm-dai.c | 8 +++++---
>  1 file changed, 5 insertions(+), 3 deletions(-)
> 
> diff --git a/sound/soc/qcom/qdsp6/q6apm-dai.c b/sound/soc/qcom/qdsp6/q6apm-dai.c
> index c9404b5934c7..148c3fb77168 100644
> --- a/sound/soc/qcom/qdsp6/q6apm-dai.c
> +++ b/sound/soc/qcom/qdsp6/q6apm-dai.c
> @@ -299,15 +299,17 @@ static int q6apm_dai_trigger(struct snd_soc_component *component,
>  {
>  	struct snd_pcm_runtime *runtime = substream->runtime;
>  	struct q6apm_dai_rtd *prtd = runtime->private_data;
> -	int ret = 0;
> +	int ret = 0, i;
>  
>  	switch (cmd) {
>  	case SNDRV_PCM_TRIGGER_START:
>  	case SNDRV_PCM_TRIGGER_RESUME:
>  	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
>  		 /* start writing buffers for playback only as we already queued capture buffers */
> -		if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
> -			ret = q6apm_write_async(prtd->graph, prtd->pcm_count, 0, 0, 0);
> +		if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
> +			for (i = 0; i < runtime->periods; i++)
> +				ret = q6apm_write_async(prtd->graph, prtd->pcm_count, 0, 0, 0);

So, all errors except the last one are ignored now?

> +		}
>  		break;
>  	case SNDRV_PCM_TRIGGER_STOP:
>  		/* TODO support be handled via SoftPause Module */
> -- 
> 2.39.5
> 

-- 
With best wishes
Dmitry