add audio(4) driver the ability to use different block sizes for play and

record modes. This makes possible to have blocks of the same duration if the
play and record formats are different. The API change is backward
compatible, so it shouldn't be noticed by current audio ports.

ok jakemsr

1 files changed, 29 insertions, 24 deletions

diff --git a/share/man/man4/audio.4 b/share/man/man4/audio.4
index ca77ad789ce..e14a6893489 100644
--- a/share/man/man4/audio.4
+++ b/share/man/man4/audio.4
@@ -1,4 +1,4 @@
-.\"	$OpenBSD: audio.4,v 1.50 2007/12/06 19:41:28 deanna Exp $
+.\"	$OpenBSD: audio.4,v 1.51 2008/03/22 11:05:31 ratchov Exp $
 .\"	$NetBSD: audio.4,v 1.20 1998/05/28 17:27:15 augustss Exp $
 .\"
 .\" Copyright (c) 1996 The NetBSD Foundation, Inc.
@@ -35,7 +35,7 @@
 .\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 .\" POSSIBILITY OF SUCH DAMAGE.
 .\"
-.Dd $Mdocdate: December 6 2007 $
+.Dd $Mdocdate: March 22 2008 $
 .Dt AUDIO 4
 .Os
 .Sh NAME
@@ -367,6 +367,11 @@ or a bitwise OR combination of the three.
 Only full-duplex audio devices support
 simultaneous record and playback.
 .Pp
+.Va blocksize
+is used to attempt to set both play and record block sizes
+to the same value, it is left for compatibility only and
+its use is discouraged.
+.Pp
 .Va hiwat
 and
 .Va lowat
@@ -384,27 +389,6 @@ is the maximum value and for
 .Va lowat
 75% of
 .Va hiwat .
-.Pp
-.Va blocksize
-sets the current audio blocksize.
-The generic
-.Nm audio
-driver layer and the hardware driver have the
-opportunity to adjust this block size to get it within
-implementation-required limits.
-Upon return from an
-.Dv AUDIO_SETINFO
-call, the actual blocksize set is returned in this field.
-Normally the
-.Va blocksize
-is calculated to correspond to 50ms of sound and it is recalculated
-when the encoding parameter changes, but if the
-.Va blocksize
-is set explicitly this value becomes sticky, i.e., it remains
-even when the encoding is changed.
-The stickiness can be cleared by reopening the device or setting the
-.Va blocksize
-to 0.
 .Bd -literal
 struct audio_prinfo {
 	u_int	sample_rate;	/* sample rate in samples/s */
@@ -507,13 +491,34 @@ The available ports can be found in
 .Va buffer_size
 is the total size of the audio buffer.
 The buffer size divided by the
-.Va blocksize
+.Va block_size
 gives the maximum value for
 .Va hiwat .
 Currently the
 .Va buffer_size
 can only be read and not set.
 .Pp
+.Va block_size
+sets the current audio block size.
+The generic
+.Nm audio
+driver layer and the hardware driver have the
+opportunity to adjust this block size to get it within
+implementation-required limits.
+Upon return from an
+.Dv AUDIO_SETINFO
+call, the actual block_size set is returned in this field.
+Normally the
+.Va block_size
+is calculated to correspond to 50ms of sound and it is recalculated
+when the encoding parameter changes, but if the
+.Va block_size
+is set explicitly this value becomes sticky, i.e., it remains
+even when the encoding is changed.
+The stickiness can be cleared by reopening the device or setting the
+.Va block_size
+to 0.
+.Pp
 The
 .Va seek
 and