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diff --git a/share/man/man4/snd_uaudio.4 b/share/man/man4/snd_uaudio.4
--- a/share/man/man4/snd_uaudio.4
+++ b/share/man/man4/snd_uaudio.4
@@ -27,7 +27,7 @@
.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
.\" POSSIBILITY OF SUCH DAMAGE.
.\"
-.Dd November 12, 2016
+.Dd January 29, 2024
.Dt SND_UAUDIO 4
.Os
.Sh NAME
@@ -51,24 +51,74 @@
.Sh DESCRIPTION
The
.Nm
-driver provides support for
-.Tn USB
-audio class devices and
-.Tn USB
-MIDI class devices.
+driver provides support for USB audio class devices and USB MIDI class devices.
.Pp
-A
-.Tn USB
-audio device consists of a number of components:
-input terminals (e.g.\& USB digital input), output terminals (e.g.\&
-speakers), and a number of units in between (e.g.\& volume control).
+A USB audio device consists of a number of components: input terminals (e.g.\&
+USB digital input), output terminals (e.g.\& speakers), and a number of units
+in between (e.g.\& volume control).
.Pp
Refer to the
.Ql USB Audio Class Specification
for more information.
+.Ss Runtime Configuration
+.Nm
+provides the following
+.Xr sysctl 8
+variables which can be modified during runtime:
+.Bl -tag -width indent
+.It Va hw.usb.uaudio.buffer_ms
+Buffering delay in milliseconds, from 1 to 8 (default is 4).
+Because this value is set during boot-time.
+In order for a change in this value to take effect, one has to either set
+.Va hw.usb.uaudio.buffer_ms
+in
+.Pa /boot/loader.conf
+and reboot, or set it through
+.Xr sysctl 8 ,
+and re-attach the device.
+.It Va hw.usb.uaudio.default_bits
+Default sample bits, from 0 to 32 (default is 32).
+.It Va hw.usb.uaudio.default_channels
+Default sample channels, from 0 to
+.Pa UAUDIO_CHANNELS_MAX
+(default is 0). If set to 0, the channels
+will be either 4 for USB devices running in full-speed mode, or
+.Pa UAUDIO_CHANNELS_MAX .
+.Pp
+.Pa UAUDIO_CHANNELS_MAX
+is defined as the minimum value between 64 and the highest supported channel
+number (see
+.Pa AFMT_CHANNEL_MAX ) .
+.It Va hw.usb.uaudio.default_rate
+Default sample rate.
+If set to 0, the device's defaults will be used.
+.It Va hw.usb.uaudio.handle_hid
+Let
+.Nm
+handle HID volume keys, if any (default is 1).
+.Bl -tag -width 2n
+.It 0
+Disabled.
+.It 1
+Enabled.
+.El
+.El
+.Pp
+If
+.Xr usb 4
+has been compiled with
+.Va USB_DEBUG
+on, the following
+.Xr sysctl 8
+variable is also available:
+.Bl -tag -width indent
+.It Va hw.usb.uaudio.debug
+Debug output level (default is 0).
+.El
.Sh SEE ALSO
.Xr sound 4 ,
-.Xr usb 4
+.Xr usb 4 ,
+.Xr sysctl 8
.Rs
.%T "USB Audio Class Specifications"
.%U http://www.usb.org/developers/docs/devclass_docs/
@@ -86,9 +136,7 @@
by
.An Hiten Pandya Aq Mt hmp@FreeBSD.org .
.Sh BUGS
-The
-.Tn PCM
-framework in
+The PCM framework in
.Fx
only supports synchronous device detach.
That means all mixer and DSP character devices belonging to a given
@@ -104,9 +152,7 @@
.Va dev.pcm.%d.[play|rec].vchanrate
sysctls.
.Pp
-The
-.Tn PCM
-framework in
+The PCM framework in
.Fx
currently doesn't support the full set of USB audio mixer
controls.

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