snd_pcm_attach_substream 483 include/sound/pcm.h int snd_pcm_attach_substream(struct snd_pcm *pcm, int stream, struct file *file, snd_pcm_attach_substream 2028 sound/core/pcm_native.c err = snd_pcm_attach_substream(pcm, stream, file, &substream);