1 .\" $NetBSD: uaudio.4,v 1.15 2002/02/12 19:53:57 jdolecek Exp $
3 .\" Copyright (c) 1999 The NetBSD Foundation, Inc.
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6 .\" This code is derived from software contributed to The NetBSD Foundation
7 .\" by Lennart Augustsson.
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37 .Nd USB audio and MIDI device driver
39 To compile this driver into the kernel, place the following lines in your
40 kernel configuration file:
41 .Bd -ragged -offset indent
44 .Cd "device snd_uaudio"
47 Alternatively, to load the driver as a module at boot time, place the
50 .Bd -literal -offset indent
56 driver provides support for
58 audio class devices and
64 audio device consists of a number of components:
65 input terminals (e.g.\& USB digital input), output terminals (e.g.\&
66 speakers), and a number of units in between (e.g.\& volume control).
69 .Ql USB Audio Class Specification
75 .%T "USB Audio Class Specifications"
76 .%U http://www.usb.org/developers/devclass_docs/
81 driver first appeared in
84 This manual page was adopted from
89 .An Hiten Pandya Aq hmp@FreeBSD.org .
95 only supports synchronous device detach.
96 That means all mixer and DSP character devices belonging to a given
97 USB audio device must be closed when receiving an error on a DSP read,
98 a DSP write or a DSP IOCTL request.
99 Else the USB audio driver will wait for this to happen, preventing
100 enumeration of new devices on the parenting USB controller.
102 Some USB audio devices might refuse to work properly unless the sample
103 rate is configured the same for both recording and playback, even if
104 only simplex is used.
106 .Va dev.pcm.%d.[play|rec].vchanrate
113 currently doesn't support the full set of USB audio mixer
115 Some mixer controls are only available as