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Commit e4fba9b5 authored by Koro Chen's avatar Koro Chen Committed by Mark Brown
Browse files

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: default avatarKoro Chen <koro.chen@mediatek.com>
Signed-off-by: default avatarMark Brown <broonie@kernel.org>
parent 6ff33f39

sound/soc/mediatek/mtk-afe-pcm.c

+17 −0
Original line number Diff line number Diff line
@@ -549,6 +549,23 @@ static int mtk_afe_dais_startup(struct snd_pcm_substream *substream, 
	memif->substream = substream;



	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,

					    SNDRV_PCM_HW_PARAM_PERIODS);

	if (ret < 0)