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SND_UAUDIO(4)	       FreeBSD Kernel Interfaces Manual		 SND_UAUDIO(4)

NAME
     snd_uaudio	-- USB audio and MIDI device driver

SYNOPSIS
     To	compile	this driver into the kernel, place the following lines in your
     kernel configuration file:

	   device sound
	   device usb
	   device snd_uaudio

     Alternatively, to load the	driver as a module at boot time, place the
     following line in loader.conf(5):

	   snd_uaudio_load="YES"

DESCRIPTION
     The snd_uaudio driver provides support for	USB audio class	devices	and
     USB MIDI class devices.

     A 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).

     Refer to the `USB Audio Class Specification' for more information.

SEE ALSO
     sound(4), usb(4)

     USB Audio Class Specifications,
     http://www.usb.org/developers/devclass_docs/.

HISTORY
     The snd_uaudio driver first appeared in FreeBSD 4.7.

AUTHORS
     This manual page was adopted from NetBSD 1.6 and modified for FreeBSD by
     Hiten Pandya <hmp@FreeBSD.org>.

BUGS
     The PCM framework in FreeBSD only supports	synchronous device detach.
     That means	all mixer and DSP character devices belonging to a given USB
     audio device must be closed when receiving	an error on a DSP read,	a DSP
     write or a	DSP IOCTL request.  Else the USB audio driver will wait	for
     this to happen, preventing	enumeration of new devices on the parenting
     USB controller.

     Some USB audio devices might refuse to work properly unless the sample
     rate is configured	the same for both recording and	playback, even if only
     simplex is	used.  See the dev.pcm.%d.[play|rec].vchanrate sysctls.

     The PCM framework in FreeBSD currently doesn't support the	full set of
     USB audio mixer controls.	Some mixer controls are	only available as
     dev.pcm.%d.mixer sysctls.

FreeBSD	10.2			March 19, 2015			  FreeBSD 10.2

NAME | SYNOPSIS | DESCRIPTION | SEE ALSO | HISTORY | AUTHORS | BUGS

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