freebsd-skq/share/man/man4/snd_uaudio.4
Hiten Pandya 5dec156e2b Add a manual page for the USB Audio support in FreeBSD,
interfaced via the PCM framework.

This manual page was obtained from NetBSD, and the required
changes were made to adapt it to our uaudio driver.

Pre-cursor review:	joe@
2003-11-10 20:25:40 +00:00

97 lines
3.2 KiB
Groff

.\" $FreeBSD$
.\" $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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.Dd November 10, 2003
.Dt UAUDIO 4
.Os
.Sh NAME
.Nm uaudio
.Nd USB audio device driver
.Sh SYNOPSIS
.Cd "device pcm"
.Cd "device usb"
.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 pcm 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
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.