From 7f2430cda819a9ecb1df5a0f3ef4f1c20db3f811 Mon Sep 17 00:00:00 2001
From: Stephan Gerhold <stephan@gerhold.net>
Date: Mon, 30 Mar 2020 19:52:10 +0200
Subject: [PATCH] ASoC: qcom: q6asm-dai: Add SNDRV_PCM_INFO_BATCH flag
Git-commit: 7f2430cda819a9ecb1df5a0f3ef4f1c20db3f811
Patch-mainline: v5.7-rc1
References: jsc#SLE-16518
At the moment, playing audio with PulseAudio with the qdsp6 driver
results in distorted sound. It seems like its timer-based scheduling
does not work properly with qdsp6 since setting tsched=0 in
the PulseAudio configuration avoids the issue.
Apparently this happens when the pointer() callback is not accurate
enough. There is a SNDRV_PCM_INFO_BATCH flag that can be used to stop
PulseAudio from using timer-based scheduling by default.
According to https://www.alsa-project.org/pipermail/alsa-devel/2014-March/073816.html:
The flag is being used in the sense explained in the previous audio
meeting -- the data transfer granularity isn't fine enough but aligned
to the period size (or less).
q6asm-dai reports the position as multiple of
prtd->pcm_count = snd_pcm_lib_period_bytes(substream)
so it indeed just a multiple of the period size.
Therefore adding the flag here seems appropriate and makes audio
work out of the box.
Fixes: 2a9e92d371db ("ASoC: qdsp6: q6asm: Add q6asm dai driver")
Signed-off-by: Stephan Gerhold <stephan@gerhold.net>
Reviewed-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Cc: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20200330175210.47518-1-stephan@gerhold.net
Signed-off-by: Mark Brown <broonie@kernel.org>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
sound/soc/qcom/qdsp6/q6asm-dai.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/sound/soc/qcom/qdsp6/q6asm-dai.c b/sound/soc/qcom/qdsp6/q6asm-dai.c
index f6c7cddf08e8..125af00bba53 100644
--- a/sound/soc/qcom/qdsp6/q6asm-dai.c
+++ b/sound/soc/qcom/qdsp6/q6asm-dai.c
@@ -78,7 +78,7 @@ struct q6asm_dai_data {
};
static const struct snd_pcm_hardware q6asm_dai_hardware_capture = {
- .info = (SNDRV_PCM_INFO_MMAP |
+ .info = (SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_BATCH |
SNDRV_PCM_INFO_BLOCK_TRANSFER |
SNDRV_PCM_INFO_MMAP_VALID |
SNDRV_PCM_INFO_INTERLEAVED |
@@ -100,7 +100,7 @@ static const struct snd_pcm_hardware q6asm_dai_hardware_capture = {
};
static struct snd_pcm_hardware q6asm_dai_hardware_playback = {
- .info = (SNDRV_PCM_INFO_MMAP |
+ .info = (SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_BATCH |
SNDRV_PCM_INFO_BLOCK_TRANSFER |
SNDRV_PCM_INFO_MMAP_VALID |
SNDRV_PCM_INFO_INTERLEAVED |
--
2.16.4