$NetBSD: uaudio.4,v 1.15 2002/02/12 19:53:57 jdolecek Exp $ Copyright (c) 1999 The NetBSD Foundation, Inc. All rights reserved. This code is derived from software contributed to The NetBSD Foundation by Lennart Augustsson. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaime...
NAMEsnd_uaudio - USB audio and MIDI device driver
SYNOPSISTo 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:
DESCRIPTIONThe sysctl Cm net.inet.tcp.syncookies 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 ALSOsound(4), usb(4)
- "USB Audio Class Specifications"
HISTORYThe sysctl Cm net.inet.tcp.syncookies driver first appeared in Fx 4.7 .
AUTHORSThis manual page was adopted from Nx 1.6 and modified for Fx by An Hiten Pandya Aq Mt hmp@FreeBSD.org .
BUGSThe PCM framework in Fx 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 Fx currently doesn't support the full set of USB audio mixer controls. Some mixer controls are only available as dev.pcm.%d.mixer sysctls.