+ if (!pawd) { /* not yet started */
+ assert(wn->btrn);
+ ret = btr_node_status(wn->btrn, wn->min_iqs, BTR_NT_LEAF);
+ if (ret != 0)
+ goto min_delay;
+ return; /* no data available */
+ }
+ if (!wn->btrn) { /* EOF */
+ if (!pawd->thread_btrn) /* ready to exit */
+ goto min_delay;
+ /* wait for the play thread to terminate */
+ goto timeout;
+ }
+ pthread_mutex_lock(&pawd->mutex);
+ ret = btr_node_status(wn->btrn, wn->min_iqs, BTR_NT_LEAF);
+ pthread_mutex_unlock(&pawd->mutex);
+ if (ret != 0)
+ goto min_delay;
+ /*
+ * Even though the node status is zero, we might have data available,
+ * but the output buffer is full. If we don't set a timeout here, we
+ * are woken up only if new data arrives, which might be too late and
+ * result in a buffer underrun in the playing thread. To avoid this we
+ * never sleep longer than the (default) buffer time.
+ */
+timeout:
+ return sched_request_timeout_ms(20, s);
+min_delay: