snd_uaudio(4) USB audio and MIDI device driver


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.conf5:



The 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.


The driver first appeared in Fx 4.7 .


This manual page was adopted from Nx 1.6 and modified for Fx by An Hiten Pandya Aq [email protected] .


The PCM framework in Fx , 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. It is necessary to allow the device un-registration to complete successfully, otherwise the PCM layer will panic.