On Thu, 30 Jul 2020 17:27:58 +0200, Pierre-Louis Bossart wrote: > > > > >> Is this patch required if you've already constrained the period sizes for the > >> platform driver in patch1? > > > > Yes or alsa will select 320 as default period size for it. > > ok, then that's a miss in your patch1. 320 samples is a multiple of > 1ms for 48kHz rates. I think it was valid only for the 16kHz VoIP > paths used in some versions of Android, but that we don't support in > the upstream code. > > To build on Takashi's answer, the real ask here is to require that the > period be a multiple of 1ms, because that's the fundamental > design/limitation of firmware. It doesn't matter if it's 48, 96, 192, > 240, 480, 960 samples. If the 1ms alignment is the condition, it can be better with a different hw_params constraint. We can use snd_pcm_hw_constraint_step() for such a purpose. thanks, Takashi
