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ASoC: mediatek: Increase periods_min in capture 

In capture, there is chance that hw_ptr reported at IRQ is
a little smaller than period_size due to internal AFE buffer.
In the case of ping-pong buffer:

|xxxxxxxxxxxxxxxxxxxxxxxxxxxx--|-----------------------------|
                            hw_ptr < period_size

This available buffer will not be read since its size is smaller than
avail_min (which is period_size by default), and read thread continues
to sleep. If the next hw_ptr is just a little larger than buffer_size,
overrun occurs. One more period can hold the possible unread buffer.

Signed-off-by: Koro Chen <koro.chen@mediatek.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Koro Chen 2015-09-14 14:51:17 +08:00 committed by Mark Brown
parent 6ff33f3902
commit e4fba9b5be
1 changed files with 17 additions and 0 deletions
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17
sound/soc/mediatek/mtk-afe-pcm.c
View File

@ -549,6 +549,23 @@ static int mtk_afe_dais_startup(struct snd_pcm_substream *substream,
memif->substream = substream; memif->substream = substream;
snd_soc_set_runtime_hwparams(substream, &mtk_afe_hardware); snd_soc_set_runtime_hwparams(substream, &mtk_afe_hardware);
/*
* Capture cannot use ping-pong buffer since hw_ptr at IRQ may be
* smaller than period_size due to AFE's internal buffer.
* This easily leads to overrun when avail_min is period_size.
* One more period can hold the possible unread buffer.
*/
if (substream->stream == SNDRV_PCM_STREAM_CAPTURE) {
ret = snd_pcm_hw_constraint_minmax(runtime,
SNDRV_PCM_HW_PARAM_PERIODS,
3,
mtk_afe_hardware.periods_max);
if (ret < 0) {
dev_err(afe->dev, "hw_constraint_minmax failed\n");
return ret;
}
}
ret = snd_pcm_hw_constraint_integer(runtime, ret = snd_pcm_hw_constraint_integer(runtime,
SNDRV_PCM_HW_PARAM_PERIODS); SNDRV_PCM_HW_PARAM_PERIODS);
if (ret < 0) if (ret < 0)