[src/netbsd-6]: src/sys/dev Apply patch (requested by nat in ticket #1457):

[snj <snj%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/5d3127e0d157
branches:  netbsd-6
changeset: 777190:5d3127e0d157
user:      snj <snj%NetBSD.org@localhost>
date:      Fri Jul 21 04:06:50 2017 +0000

description:
Apply patch (requested by nat in ticket #1457):
Fix occasional stuttering that can be caused by ringbuffer overflow.

diffstat:

 sys/dev/audio.c |  8 ++++++--
 1 files changed, 6 insertions(+), 2 deletions(-)

diffs (36 lines):

diff -r c790a24731d6 -r 5d3127e0d157 sys/dev/audio.c
--- a/sys/dev/audio.c   Fri Jul 21 04:02:12 2017 +0000
+++ b/sys/dev/audio.c   Fri Jul 21 04:06:50 2017 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: audio.c,v 1.257.2.4 2012/06/13 19:14:17 riz Exp $      */
+/*     $NetBSD: audio.c,v 1.257.2.5 2017/07/21 04:06:50 snj Exp $      */
 
 /*-
  * Copyright (c) 2008 The NetBSD Foundation, Inc.
@@ -155,7 +155,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: audio.c,v 1.257.2.4 2012/06/13 19:14:17 riz Exp $");
+__KERNEL_RCSID(0, "$NetBSD: audio.c,v 1.257.2.5 2017/07/21 04:06:50 snj Exp $");
 
 #include "audio.h"
 #if NAUDIO > 0
@@ -2950,6 +2950,9 @@
                return;
        }
 
+       if (audio_stream_get_used(&cb->s) > (cb->usedhigh - cb->blksize))
+               goto done;
+
 #ifdef AUDIO_INTR_TIME
        {
                struct timeval tv;
@@ -3028,6 +3031,7 @@
        }
 
        DPRINTFN(5, ("audio_pint: outp=%p cc=%d\n", cb->s.outp, blksize));
+done:
        if (hw->trigger_output == NULL) {
                error = hw->start_output(sc->hw_hdl, __UNCONST(cb->s.outp),
                    blksize, audio_pint, (void *)sc);