On 10/02/2020 16.38, Takashi Iwai wrote:
On Mon, 10 Feb 2020 15:28:44 +0100, Peter Ujfalusi wrote:
Hi Takashi,
--- a/sound/soc/soc-pcm.c +++ b/sound/soc/soc-pcm.c @@ -1151,7 +1151,7 @@ static snd_pcm_uframes_t soc_pcm_pointer(struct snd_pcm_substream *substream) } delay += codec_delay;
- runtime->delay = delay;
- runtime->delay += delay;
Is it correct? delay already takes runtime->delay as its basis, so it'll result in a double.
The delay here is coming from the DAI and the codec. The runtime->delay hold the PCM (DMA) caused delay.
Well, let's take a look at soc_pcm_pointer():
/* clearing the previous total delay */ runtime->delay = 0;
offset = snd_soc_pcm_component_pointer(substream);
/* base delay if assigned in pointer callback */ delay = runtime->delay;
delay += snd_soc_dai_delay(cpu_dai, substream);
for_each_rtd_codec_dai(rtd, i, codec_dai) { codec_delay = max(codec_delay, snd_soc_dai_delay(codec_dai, substream)); } delay += codec_delay;
runtime->delay = delay;
So, the code reads the current runtime->delay and saves it as delay variable. Then it adds the max delay from codec DAIs, and stores back to runtime->delay.
If we change the last line to runtime->delay += delay; it'll add to the already existing value again, so it'll be doubly if runtime->delay was non-zero beforehand.
Yes, you are right. The change is added by 9fb4c2bf130b ASoC: soc-pcm: Use delay set in component pointer function
which I have missed, apparently.
That said, judging from the code, I believe the current soc-pcm.c code needs no change.
Yes, there is no need to change soc-pcm.
thanks,
Takashi
- Péter
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