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authorisaki <isaki@NetBSD.org>2020-03-28 08:35:36 +0000
committerisaki <isaki@NetBSD.org>2020-03-28 08:35:36 +0000
commitfdb148af541857520458ef034a69e60ed3b5ccb4 (patch)
tree33074db910790e9ec440282124523dfcf5d33d6e /sys/dev/audio
parent8d154765fac619e7211682a22b8469ccbddbd3a6 (diff)
Reduce default AUDIO_BLK_MS from 40msec to 10msec on all platform except m68k
(m68k uses 40msec default as before). And remove the option from GENERIC. - It's not good idea to set such parameter in individual GENERICs. - 4msec is (probably no problem for most modern real hardware but) too aggressive to be default. - 10msec is too severe for antique machines but it's hard to draw a line.
Diffstat (limited to 'sys/dev/audio')
-rw-r--r--sys/dev/audio/audiodef.h14
1 files changed, 11 insertions, 3 deletions
diff --git a/sys/dev/audio/audiodef.h b/sys/dev/audio/audiodef.h
index 3b0700430ca..a88c2ab2a30 100644
--- a/sys/dev/audio/audiodef.h
+++ b/sys/dev/audio/audiodef.h
@@ -1,4 +1,4 @@
-/* $NetBSD: audiodef.h,v 1.12 2020/03/05 15:18:55 riastradh Exp $ */
+/* $NetBSD: audiodef.h,v 1.13 2020/03/28 08:35:36 isaki Exp $ */
/*
* Copyright (C) 2017 Tetsuya Isaki. All rights reserved.
@@ -44,13 +44,21 @@
/*
* Hardware blocksize in msec.
- * We use 40 msec as default. (1 / 40ms) = 25 = 5^2.
+ * We use 10 msec as default for most platforms. But it's too severe for
+ * most m68k.
+ *
+ * 40 msec was initially choosen for the following reason:
+ * (1 / 40ms) = 25 = 5^2. Thus, the frequency is factored by 5.
* In this case, the number of frames in a block can be an integer
* even if the frequency is a multiple of 100 (44100, 48000, etc),
* or even if 15625Hz (vs(4)).
*/
#if !defined(AUDIO_BLK_MS)
-#define AUDIO_BLK_MS 40
+# if defined(__m68k__)
+# define AUDIO_BLK_MS 40
+# else
+# define AUDIO_BLK_MS 10
+# endif
#endif
/*