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authorKoro Chen <koro.chen@mediatek.com>2015-09-14 14:51:17 +0800
committerMark Brown <broonie@kernel.org>2015-09-14 18:13:54 +0100
commite4fba9b5be12d577d2e2c19fdca6b0744c3f271e (patch)
treea5baa4b7e21809e256239781d862b5a1dc0eb9d6 /sound
parent6ff33f3902c3b1c5d0db6b1e2c70b6d76fba357f (diff)
downloadlinux-e4fba9b5be12d577d2e2c19fdca6b0744c3f271e.tar.gz
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>
Diffstat (limited to 'sound')
-rw-r--r--sound/soc/mediatek/mtk-afe-pcm.c17
1 files changed, 17 insertions, 0 deletions
diff --git a/sound/soc/mediatek/mtk-afe-pcm.c b/sound/soc/mediatek/mtk-afe-pcm.c
index d190fe017559..f5baf3c38863 100644
--- a/sound/soc/mediatek/mtk-afe-pcm.c
+++ b/sound/soc/mediatek/mtk-afe-pcm.c
@@ -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)