document the new kern.audio node; OK ratchov@

1 files changed, 26 insertions, 2 deletions

diff --git a/lib/libc/sys/sysctl.2 b/lib/libc/sys/sysctl.2
index c7d9f6f4a1f..5f6428bc7ea 100644
--- a/lib/libc/sys/sysctl.2
+++ b/lib/libc/sys/sysctl.2
@@ -1,4 +1,4 @@
-.\"	$OpenBSD: sysctl.2,v 1.5 2018/05/16 15:24:10 visa Exp $
+.\"	$OpenBSD: sysctl.2,v 1.6 2018/05/26 12:47:52 schwarze Exp $
 .\"
 .\" Copyright (c) 1993
 .\"	The Regents of the University of California.  All rights reserved.
@@ -27,7 +27,7 @@
 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 .\" SUCH DAMAGE.
 .\"
-.Dd $Mdocdate: May 16 2018 $
+.Dd $Mdocdate: May 26 2018 $
 .Dt SYSCTL 2
 .Os
 .Sh NAME
@@ -413,6 +413,7 @@ information.
 .It Sy "Second level name" Ta Sy "Type" Ta Sy "Changeable"
 .It Dv KERN_ALLOWKMEM Ta "integer" Ta "yes"
 .It Dv KERN_ARGMAX Ta "integer" Ta "no"
+.It Dv KERN_AUDIO Ta "node" Ta "yes"
 .It Dv KERN_BOOTTIME Ta "struct timeval" Ta "no"
 .It Dv KERN_CACHEPCT Ta "integer" Ta "yes"
 .It Dv KERN_CCPU Ta "integer" Ta "no"
@@ -495,6 +496,29 @@ this variable may not be changed.
 .It Dv KERN_ARGMAX Pq Va kern.argmax
 The maximum number of bytes allowed among the arguments to
 .Xr exec 3 .
+.It Dv KERN_AUDIO Pq Va kern.audio
+Control device-independent aspects of the
+.Xr audio 4
+and
+.Xr mixer 4
+subsystem.
+Currently, there is one subnode:
+.Bl -column "KERN_AUDIO_RECORD" "integer" "Changeable" -offset indent
+.It Sy "Third level name" Ta Sy "Type" Ta Sy "Changeable"
+.It Dv KERN_AUDIO_RECORD Ta "integer" Ta "yes"
+.El
+.Pp
+Its meaning is as follows:
+.Bl -tag -width "123456"
+.It Dv KERN_AUDIO_RECORD Pq Va kern.audio.record
+If set to the default value of 0, recording is muted by default
+for all audio devices.
+Otherwise, audio recording is enabled by default.
+For individual devices, this setting can be overridden with the
+.Xr mixerctl 1
+.Va record.enable
+variable.
+.El
 .It Dv KERN_BOOTTIME Pq Va kern.boottime
 A
 .Li struct timeval