.\" $NetBSD: uaudio.4,v 1.15 2002/02/12 19:53:57 jdolecek Exp $
.\"
.\" Copyright (c) 1999 The NetBSD Foundation, Inc.
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.\"
.\" This code is derived from software contributed to The NetBSD Foundation
.\" by Lennart Augustsson.
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.\" $FreeBSD: head/share/man/man4/snd_uaudio.4 267938 2014-06-26 21:46:14Z bapt $
.\"
.Dd January 8, 2015
.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
uaudio_load="YES"
.Ed
.Sh DESCRIPTION
The
.Nm
driver provides support for
.Tn USB
audio class devices and
.Tn 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).
.Pp
Refer to the
.Ql USB Audio Class Specification
for more information.
.Sh SEE ALSO
.Xr sound 4 ,
.Xr usb 4
.Rs
.%T "USB Audio Class Specifications"
.%U http://www.usb.org/developers/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
.Tn PCM
framework in
.Fx ,
as of this writing, does not handle device un-registrations in a properly
abstracted manner, i.e., a detach request is refused by the
.Tn PCM
framework if the device is in use.
It is necessary to allow the device un-registration to complete
successfully, otherwise the
.Tn PCM
layer will panic.