snd_uaudio(4) [debian man page]

SND_UAUDIO(4)						   BSD Kernel Interfaces Manual 					     SND_UAUDIO(4)

NAME

     snd_uaudio -- USB audio 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.

     A USB audio device consists of a number of components: input terminals (e.g. USB digital input), output terminals (e.g. speakers), and a num-
     ber 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, as of this writing, does not handle device un-registrations in a properly abstracted manner, i.e., a detach
     request is refused by the PCM framework if the device is in use.  For 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.

BSD
								 December 15, 2005							       BSD

UAUDIO(4)						   BSD Kernel Interfaces Manual 						 UAUDIO(4)

NAME

     uaudio -- USB audio device driver

SYNOPSIS

     uaudio* at uhub?
     audio*  at audiobus?

DESCRIPTION

     The uaudio driver provides support for USB audio 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).	The following types of units are handled by the uaudio driver and are accessible via the
     mixer (see audio(4)) interface:
	mixer	      A mixer has a number of inputs and one output.  Each input has a control that determines its volume in the output.  The name
		      of the control is mixN-S, where N is a number that identifies which mixer it is and S which input.
	selector      A selector unit selects one of multiple audio sources such as mic-in and line-in.  The name of the control is
		      selN-S1S2S3..., where N is a number that identifies which selector unit it is and the sequence of Sn indicates candidate
		      units for the audio source.
	feature       A feature unit changes the sound in some way, like bass, treble, mute, or volume.  The name of the control is determined in
		      a heuristic way.	If the unit changes the sound to a speaker output terminal, the names of the controls may be out-
		      puts.speaker.bass, outputs.speaker.treble, outputs.speaker.mute, outputs.speaker, or likewise.
	processing    A processing unit does one of a number of audio processing functions (e.g., channel up-down mixing, Dolby ProLogic, or cho-
		      rus effects).  The name of the on-off control is proN.M-enable, where N is a number that identifies which processing unit it
		      is and M which kind.  Depending on the type of processing unit there may be other controls as well.
	extension     An extension unit performs some unspecified audio processing The name of the on-off control is extN-enable, where N is a
		      number that identifies which processing unit it is.

     For more information the USB Audio class specification is indispensable reading.

SEE ALSO

     audio(4), usb(4)

     USB Approved Class Specification Documents, http://www.usb.org/developers/devclass_docs/.

HISTORY

     The uaudio driver appeared in NetBSD 1.5.

BUGS

     There is no support for multiple-endpoints audio stream, adaptive recording, async playback, and TYPE-II/III formats.

     There is the possibility that a device has multiple mixer items which have the same name.

BSD
								September 20, 2011							       BSD