1.\" $NetBSD: uaudio.4,v 1.15 2002/02/12 19:53:57 jdolecek Exp $ 2.\" 3.\" Copyright (c) 1999 The NetBSD Foundation, Inc. 4.\" All rights reserved. 5.\" 6.\" This code is derived from software contributed to The NetBSD Foundation 7.\" by Lennart Augustsson. 8.\" 9.\" Redistribution and use in source and binary forms, with or without 10.\" modification, are permitted provided that the following conditions 11.\" are met: 12.\" 1. Redistributions of source code must retain the above copyright 13.\" notice, this list of conditions and the following disclaimer. 14.\" 2. Redistributions in binary form must reproduce the above copyright 15.\" notice, this list of conditions and the following disclaimer in the 16.\" documentation and/or other materials provided with the distribution. 17.\" 18.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 19.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 20.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 21.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 22.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 23.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 24.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 25.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 26.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 27.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 28.\" POSSIBILITY OF SUCH DAMAGE. 29.\" 30.\" $FreeBSD$ 31.\" 32.Dd November 12, 2016 33.Dt SND_UAUDIO 4 34.Os 35.Sh NAME 36.Nm snd_uaudio 37.Nd USB audio and MIDI device driver 38.Sh SYNOPSIS 39To compile this driver into the kernel, place the following lines in your 40kernel configuration file: 41.Bd -ragged -offset indent 42.Cd "device sound" 43.Cd "device usb" 44.Cd "device snd_uaudio" 45.Ed 46.Pp 47Alternatively, to load the driver as a module at boot time, place the 48following line in 49.Xr loader.conf 5 : 50.Bd -literal -offset indent 51snd_uaudio_load="YES" 52.Ed 53.Sh DESCRIPTION 54The 55.Nm 56driver provides support for 57.Tn USB 58audio class devices and 59.Tn USB 60MIDI class devices. 61.Pp 62A 63.Tn USB 64audio device consists of a number of components: 65input terminals (e.g.\& USB digital input), output terminals (e.g.\& 66speakers), and a number of units in between (e.g.\& volume control). 67.Pp 68Refer to the 69.Ql USB Audio Class Specification 70for more information. 71.Sh SEE ALSO 72.Xr sound 4 , 73.Xr usb 4 74.Rs 75.%T "USB Audio Class Specifications" 76.%U http://www.usb.org/developers/docs/devclass_docs/ 77.Re 78.Sh HISTORY 79The 80.Nm 81driver first appeared in 82.Fx 4.7 . 83.Sh AUTHORS 84This manual page was adopted from 85.Nx 1.6 86and modified for 87.Fx 88by 89.An Hiten Pandya Aq Mt hmp@FreeBSD.org . 90.Sh BUGS 91The 92.Tn PCM 93framework in 94.Fx 95only supports synchronous device detach. 96That means all mixer and DSP character devices belonging to a given 97USB audio device must be closed when receiving an error on a DSP read, 98a DSP write or a DSP IOCTL request. 99Else the USB audio driver will wait for this to happen, preventing 100enumeration of new devices on the parenting USB controller. 101.Pp 102Some USB audio devices might refuse to work properly unless the sample 103rate is configured the same for both recording and playback, even if 104only simplex is used. 105See the 106.Va dev.pcm.%d.[play|rec].vchanrate 107sysctls. 108.Pp 109The 110.Tn PCM 111framework in 112.Fx 113currently doesn't support the full set of USB audio mixer 114controls. 115Some mixer controls are only available as 116.Va dev.pcm.%d.mixer 117sysctls. 118