.\"	$NetBSD: hdaudio.4,v 1.14 2014/09/19 17:27:12 christos Exp $
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.Dd September 19, 2014
.Dt HDAUDIO 4
.Os
.Sh NAME
.Nm hdaudio
.Nd High Definition Audio device driver
.Sh SYNOPSIS
.Cd "hdaudio* at pci? dev ? function ?"
.Cd "hdafg* at hdaudiobus?"
.Cd "audio* at audiobus?"
.Pp
.Cd "options HDAUDIOVERBOSE"
.Cd "options HDAUDIO_DEBUG"
.Cd "options HDAFG_DEBUG"
.Sh DESCRIPTION
The
.Nm
device driver is expected to support any PCI device which is
compliant to the High Definition Audio Specification 1.0.
It is a replacement for
.Xr azalia 4 .
It was written from scratch following the Intel HD Audio and Microsoft
Universal Audio Architecture specifications.
.Pp
The driver consists of two interlinked components, which reflects the
hardware design.
The
.Nm
component interfaces with a PCI/PCIe bus and provides an
.Xr hdaudiobus 4
onto which different function groups attach.
Each function group (e.g. audio, vendor-specific modem) is exported as a
separate child device of the
.Nm
controller.
Audio function groups (a.k.a. audio codec) are exported as
.Xr hdafg 4
devices.
.Pp
Audio codecs are available from a number of manufacturers and are made up of a
number of widgets (e.g. audio mixer, output pin, analog-to-digital converter).
The way the widgets are interlinked varies significantly between
implementations.
The tree of widgets must be parsed and mapped to
.Xr mixer 4
controls.
As part of this process, loops in the inter-codec links must be detected
and muted, bi-directional pins must be set up appropriately and the locations
of pins determined.
Unlike the
.Xr azalia 4
driver (which tends to generate a large number of unclearly named
.Xr mixer 4
controls),
.Nm
works backwards by starting with a list of desired, consistent and compatible
.Xr mixer 4
controls and configuring/discovering appropriate widget link routes to fit.
.Pp
By following the published mechanisms for common implementations of widget
parsing, it is expected that nearly all High Definition Audio devices will
be supported without requiring per-device quirks.
.Sh HARDWARE
In addition to many on-board sound cards included in mainboards, the following
add-on card is supported:
.Bl -tag
.It TerraTec Aureon 7.1 PCIe
.El
.Sh SEE ALSO
.Xr audio 4 ,
.Xr mixer 4 ,
.Xr pci 4 ,
.Xr hdaudioctl 8 ,
.Pp
.Lk http://www.intel.com/design/chipsets/hdaudio.htm "Intel High Definition Audio"
.Pp
.Lk http://www.microsoft.com/whdc/device/audio/ "Audio Device Technologies for Windows"
.Sh HISTORY
The
.Nm
device driver appeared in
.Nx 5.1 .
.Sh AUTHORS
The
.Nm
driver was written by
.An Jared McNeill Aq Mt jmcneill@NetBSD.org
under contract by
.Lk http://www.precedence.co.uk/ "Precedence Technologies Ltd."
The UAA-compliant widget parser is derived from the
.Fx
snd_hda(4) driver.
.Sh BUGS
The following items are not yet implemented:
.Bl -bullet
.It
Improve power management support when driver is idle
.It
Add support for non-PCM output formats
.It
Handle unsolicited RIRB messages
.It
Modem function groups
.El