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 number
of units in between (e.g. volume control).

Refer to the `USB Audio Class Specification' for more infor

mation.

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 al

low 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