diff --git a/share/man/man4/snd_uaudio.4 b/share/man/man4/snd_uaudio.4
index 04dc10ccaa25..b6a6c06a2312 100644
--- a/share/man/man4/snd_uaudio.4
+++ b/share/man/man4/snd_uaudio.4
@@ -1,105 +1,180 @@
 .\" $NetBSD: uaudio.4,v 1.15 2002/02/12 19:53:57 jdolecek Exp $
 .\"
 .\" Copyright (c) 1999 The NetBSD Foundation, Inc.
 .\" All rights reserved.
 .\"
 .\" This code is derived from software contributed to The NetBSD Foundation
 .\" by Lennart Augustsson.
 .\"
 .\" Redistribution and use in source and binary forms, with or without
 .\" modification, are permitted provided that the following conditions
 .\" are met:
 .\" 1. Redistributions of source code must retain the above copyright
 .\"    notice, this list of conditions and the following disclaimer.
 .\" 2. Redistributions in binary form must reproduce the above copyright
 .\"    notice, this list of conditions and the following disclaimer in the
 .\"    documentation and/or other materials provided with the distribution.
 .\"
 .\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
 .\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 .\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 .\" PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
 .\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 .\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 .\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 .\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 .\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 .\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 .\" POSSIBILITY OF SUCH DAMAGE.
 .\"
 .Dd January 29, 2024
 .Dt SND_UAUDIO 4
 .Os
 .Sh NAME
 .Nm snd_uaudio
 .Nd USB audio and MIDI device driver
 .Sh SYNOPSIS
 To compile this driver into the kernel, place the following lines in your
 kernel configuration file:
 .Bd -ragged -offset indent
 .Cd "device sound"
 .Cd "device usb"
 .Cd "device snd_uaudio"
 .Ed
 .Pp
 Alternatively, to load the driver as a module at boot time, place the
 following line in
 .Xr loader.conf 5 :
 .Bd -literal -offset indent
 snd_uaudio_load="YES"
 .Ed
 .Sh DESCRIPTION
 The
 .Nm
 driver provides support for USB audio class devices and USB MIDI class devices.
 .Pp
 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
+If the device supports multiple configurations, and there have been no
+user-supplied values specified through the
+.Xr sysctl 8
+interface, the driver will select the best matching configuration supported by
+the device during attach.
+"Best" means the configuration with the most channels and highest quality in
+sample rate and sample size.
+.Pp
 Refer to the
 .Ql USB Audio Class Specification
 for more information.
+.Sh SYSCTL VARIABLES
+The following settings can be entered at the
+.Xr loader 8
+prompt or in
+.Xr loader.conf 5
+and can also be changed at runtime with the
+.Xr sysctl 8
+command.
+For a change to take effect during runtime, the device has to be re-attached.
+.Bl -tag -width indent
+.It Va hw.usb.uaudio.buffer_ms
+Period of audio data processed at once, in milliseconds, from 1 to 8 (default
+is 4).
+Lower values mean less latency, but this can result in audible gaps due to
+frequent CPU wakeups.
+.It Va hw.usb.uaudio.default_bits
+Preferred sample size in bits, from 0 to 32 (default is 0).
+A value of 0 sets the sample size to the maximum supported sample size.
+.Pp
+Set this to select a smaller sample size if the device supports multiple sample
+sizes.
+.It Va hw.usb.uaudio.default_channels
+Preferred number of sample channels, from 0 to 64 (default is 0).
+USB 1.1 devices are limited to 4 channels due to bandwidth constraints, unless
+a higher value is explicitly requested.
+A value of 0 sets the sample channels to the maximum supported channel number.
+.Pp
+Set this to select a smaller channel number if the device supports multiple
+channel configurations.
+.It Va hw.usb.uaudio.default_rate
+Preferred sample rate in Hz (default is 0).
+If set to 0, the device's highest supported sample rate will be used.
+.Pp
+Note that if VCHANs are enabled, the sample rate will be overridden by
+.Pa dev.pcm.%d.[play|rec].vchanrate
+(see
+.Xr sound 4 ) ,
+which can also be used to adjust the sample rate during runtime.
+.Pp
+If
+.Pa hw.usb.uaudio.default_rate
+is non-zero,
+.Pa dev.pcm.%d.[play|rec].vchanrate
+will use it as its maximum allowed value.
+.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 setting 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 loader.conf 5 ,
+.Xr loader 8 ,
+.Xr sysctl 8
 .Rs
 .%T "USB Audio Class Specifications"
 .%U http://www.usb.org/developers/docs/devclass_docs/
 .Re
 .Sh HISTORY
 The
 .Nm
 driver first appeared in
 .Fx 4.7 .
 .Sh AUTHORS
 This manual page was adopted from
 .Nx 1.6
 and modified for
 .Fx
 by
 .An Hiten Pandya Aq Mt hmp@FreeBSD.org .
 .Sh BUGS
 The PCM framework in
 .Fx
 only supports synchronous device detach.
 That means all mixer and DSP character devices belonging to a given
 USB audio device must be closed when receiving an error on a DSP read,
 a DSP write or a DSP IOCTL request.
 Else the USB audio driver will wait for this to happen, preventing
 enumeration of new devices on the parenting USB controller.
 .Pp
 Some USB audio devices might refuse to work properly unless the sample
 rate is configured the same for both recording and playback, even if
 only simplex is used.
 See the
 .Va dev.pcm.%d.[play|rec].vchanrate
 sysctls.
 .Pp
 The PCM framework in
 .Fx
-currently doesn't support the full set of USB audio mixer
-controls.
+currently does not support the full set of USB audio mixer controls.
 Some mixer controls are only available as
 .Va dev.pcm.%d.mixer
 sysctls.