UAUDIO(4)              FreeBSD Kernel Interfaces Manual              UAUDIO(4)

NAME
     uaudio -- USB audio device driver

SYNOPSIS
     device pcm
     device usb

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).

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

SEE ALSO
     pcm(4), usb(4)

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

HISTORY
     The uaudio driver first appeared in appeared in FreeBSD 4.7.

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.

FreeBSD 4.8                    November 10, 2003                   FreeBSD 4.8