freebsd-skq/share/man/man4/snd_uaudio.4

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.Dd December 15, 2005
.Dt SND_UAUDIO 4
.Os
.Sh NAME
.Nm snd_uaudio
.Nd USB audio 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
.Tn USB
audio 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"
.%O 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 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.
For
.Tn USB
and supposedly other detach-able busses, it is necessary to allow the
device un-registration to complete successfully, otherwise the driver
leaves wild pointers to invalid data structures and thus leading to a panic.