feeder_add
int feeder_add(struct pcm_channel *c, struct feeder_class *fc,
ret = feeder_add(c, fc, desc);
ret = feeder_add(c, fc, desc);
ret = feeder_add(c, fc, desc);
ret = feeder_add(c, fc, desc);
ret = feeder_add(c, fc, desc);
ret = feeder_add(c, fc, NULL);
ret = feeder_add(c, fc, desc);