alsa: Avoid busy loop at end of file.

During the drain period at the end of input the status of the alsa
buffer tree node is negative, yet we should not request a minimal
scheduler delay until the end of this period.

diff --git a/alsa_write.c b/alsa_write.c
index 047eeaa348f9017431fc42e5c121ba08f331d3b0..1c168e7b4b037f8e8853681e02254879f0912640 100644 (file)
--- a/alsa_write.c
+++ b/alsa_write.c
@@ -150,8 +150,10 @@ static void alsa_write_pre_select(struct sched *s, struct task *t)
 
        if (ret == 0)
                return;
-       if (ret < 0 || !pad)
+       if (!pad)
                return sched_min_delay(s);
+       if (ret < 0)
+               return sched_request_barrier_or_min_delay(&pad->drain_barrier, s);
        /*
         * Data is available to be written to the alsa handle.  Compute number
         * of milliseconds until next buffer underrun would occur.