[alsa-devel] Is snd_pcm_hw_constraint_mask64 really needed ?

[Chemsi Mehdi]

Dear ALSA expert ,


I am working with an alsa codec driver  where the driver is calling
err = snd_pcm_hw_constraint_mask64(substream->runtime,
SNDRV_PCM_HW_PARAM_FORMAT, formats);
my driver is already setting format before that so I wonder why this
function is called?
Looks like it is  needed to add audio constraints to substreams at
open/startup time, but why ?
what can be the issue if I do not call it ?

Please explain to me Takashi.

Thanks a lot in advance.