snd_usb_pcm_change_state
ret = snd_usb_pcm_change_state(subs, UAC3_PD_STATE_D1);
ret = snd_usb_pcm_change_state(&as->substream[0], UAC3_PD_STATE_D2);
ret = snd_usb_pcm_change_state(&as->substream[1], UAC3_PD_STATE_D2);
ret = snd_usb_pcm_change_state(&as->substream[0], UAC3_PD_STATE_D1);
ret = snd_usb_pcm_change_state(&as->substream[1], UAC3_PD_STATE_D1);
ret = snd_usb_pcm_change_state(subs, UAC3_PD_STATE_D0);
ret = snd_usb_pcm_change_state(subs, UAC3_PD_STATE_D0);