pcm_open and pcm_is_ready call fail as pcm->fd returns negative integer

Question

While trying tinyalsa in Android 9.0 pcm_is_ready call fails as pcm->fd is < 0. This is because pcm->fd = open(fn, O_RDWR|O_NONBLOCK); open call is failing. And i have made selinux as permissive. and given chmod 777 -R to /dev/snd So how to solve this issue in android???

i have made selinux as permissive. and given chmod 777 -R to /dev/snd