snd_pcm_set_state
snd_pcm_set_state(substream, SNDRV_PCM_STATE_PREPARED);
snd_pcm_set_state(substream, SNDRV_PCM_STATE_SETUP);
snd_pcm_set_state(substream, SNDRV_PCM_STATE_OPEN);
snd_pcm_set_state(substream, SNDRV_PCM_STATE_OPEN);