Thanks Stephan for finding this flag!
On 30/03/2020 18:52, Stephan Gerhold wrote:
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") Cc: Srinivas Kandagatla srinivas.kandagatla@linaro.org Signed-off-by: Stephan Gerhold stephan@gerhold.net
Reviewed-by: Srinivas Kandagatla srinivas.kandagatla@linaro.org