[src/trunk]: src/sys/dev Ensure that the low/high water marks are at least PR...

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

details:   https://anonhg.NetBSD.org/src/rev/54986fb0cc2c
branches:  trunk
changeset: 827403:54986fb0cc2c
user:      nat <nat%NetBSD.org@localhost>
date:      Thu Oct 26 22:45:00 2017 +0000

description:
Ensure that the low/high water marks are at least PREFILL_BLOCKS.

diffstat:

 sys/dev/audio.c |  10 ++++++----
 1 files changed, 6 insertions(+), 4 deletions(-)

diffs (37 lines):

diff -r 5ab5d6b2e852 -r 54986fb0cc2c sys/dev/audio.c
--- a/sys/dev/audio.c   Thu Oct 26 22:38:27 2017 +0000
+++ b/sys/dev/audio.c   Thu Oct 26 22:45:00 2017 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: audio.c,v 1.415 2017/10/26 22:38:27 nat Exp $  */
+/*     $NetBSD: audio.c,v 1.416 2017/10/26 22:45:00 nat Exp $  */
 
 /*-
  * Copyright (c) 2016 Nathanial Sloss <nathanialsloss%yahoo.com.au@localhost>
@@ -148,7 +148,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: audio.c,v 1.415 2017/10/26 22:38:27 nat Exp $");
+__KERNEL_RCSID(0, "$NetBSD: audio.c,v 1.416 2017/10/26 22:45:00 nat Exp $");
 
 #ifdef _KERNEL_OPT
 #include "audio.h"
@@ -4769,14 +4769,16 @@
                blks = ai->hiwat;
                if (blks > vc->sc_mpr.maxblks)
                        blks = vc->sc_mpr.maxblks;
-               if (blks < 2)
-                       blks = 2;
+               if (blks < PREFILL_BLOCKS + 1)
+                       blks = PREFILL_BLOCKS + 1;
                vc->sc_mpr.usedhigh = blks * vc->sc_mpr.blksize;
        }
        if (SPECIFIED(ai->lowat)) {
                blks = ai->lowat;
                if (blks > vc->sc_mpr.maxblks - 1)
                        blks = vc->sc_mpr.maxblks - 1;
+               if (blks < PREFILL_BLOCKS)
+                       blks = PREFILL_BLOCKS;
                vc->sc_mpr.usedlow = blks * vc->sc_mpr.blksize;
        }
        if (SPECIFIED(ai->hiwat) || SPECIFIED(ai->lowat)) {