This is a note to let you know that I've just added the patch titled
ASoC: qcom: q6apm-dai: Add SNDRV_PCM_INFO_BATCH flag
to the 6.2-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
asoc-qcom-q6apm-dai-add-sndrv_pcm_info_batch-flag.patch
and it can be found in the queue-6.2 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit a8e20d2585043e5de9407e3d743b291bf20901c9
Author: Srinivas Kandagatla <srinivas.kandagatla@xxxxxxxxxx>
Date: Thu Feb 9 12:28:01 2023 +0000
ASoC: qcom: q6apm-dai: Add SNDRV_PCM_INFO_BATCH flag
[ Upstream commit aa759f3f9f4394a3af65ad1772fca6cb9dd9e4cc ]
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).
q6apm-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.
Comment log inspired by Stephan Gerhold sent for q6asm-dai.c few years back.
Fixes: 9b4fe0f1cd79 ("ASoC: qdsp6: audioreach: add q6apm-dai support")
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20230209122806.18923-4-srinivas.kandagatla@xxxxxxxxxx
Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/sound/soc/qcom/qdsp6/q6apm-dai.c b/sound/soc/qcom/qdsp6/q6apm-dai.c
index bd35067a40521..7f02f5b2c33fd 100644
--- a/sound/soc/qcom/qdsp6/q6apm-dai.c
+++ b/sound/soc/qcom/qdsp6/q6apm-dai.c
@@ -64,7 +64,8 @@ struct q6apm_dai_data {
static struct snd_pcm_hardware q6apm_dai_hardware_capture = {
.info = (SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_BLOCK_TRANSFER |
SNDRV_PCM_INFO_MMAP_VALID | SNDRV_PCM_INFO_INTERLEAVED |
- SNDRV_PCM_INFO_PAUSE | SNDRV_PCM_INFO_RESUME),
+ SNDRV_PCM_INFO_PAUSE | SNDRV_PCM_INFO_RESUME |
+ SNDRV_PCM_INFO_BATCH),
.formats = (SNDRV_PCM_FMTBIT_S16_LE | SNDRV_PCM_FMTBIT_S24_LE),
.rates = SNDRV_PCM_RATE_8000_48000,
.rate_min = 8000,
@@ -82,7 +83,8 @@ static struct snd_pcm_hardware q6apm_dai_hardware_capture = {
static struct snd_pcm_hardware q6apm_dai_hardware_playback = {
.info = (SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_BLOCK_TRANSFER |
SNDRV_PCM_INFO_MMAP_VALID | SNDRV_PCM_INFO_INTERLEAVED |
- SNDRV_PCM_INFO_PAUSE | SNDRV_PCM_INFO_RESUME),
+ SNDRV_PCM_INFO_PAUSE | SNDRV_PCM_INFO_RESUME |
+ SNDRV_PCM_INFO_BATCH),
.formats = (SNDRV_PCM_FMTBIT_S16_LE | SNDRV_PCM_FMTBIT_S24_LE),
.rates = SNDRV_PCM_RATE_8000_192000,
.rate_min = 8000,
