HDAUDIO(4) | Device Drivers Manual | HDAUDIO(4) |
hdaudio
—
hdaudio* at pci? dev ? function ?
hdafg* at hdaudiobus?
audio* at audiobus?
options HDAUDIOVERBOSE
options HDAUDIO_DEBUG
options HDAFG_DEBUG
hdaudio
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 azalia(4).
It was written from scratch following the Intel HD Audio and Microsoft
Universal Audio Architecture specifications.
The driver consists of two interlinked components, which reflects
the hardware design. The hdaudio
component
interfaces with a PCI/PCIe bus and provides an
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
hdaudio
controller. Audio function groups (a.k.a.
audio codec) are exported as
hdafg(4) devices.
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 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
azalia(4) driver (which tends
to generate a large number of unclearly named
mixer(4) controls),
hdaudio
works backwards by starting with a list of
desired, consistent and compatible
mixer(4) controls and
configuring/discovering appropriate widget link routes to fit.
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.
hdaudio
device driver appeared in
NetBSD 5.1.
hdaudio
driver was written by Jared
McNeill
<jmcneill@NetBSD.org>
under contract by Precedence
Technologies Ltd. The UAA-compliant widget parser is derived from the
FreeBSD snd_hda(4) driver.
September 19, 2014 | NetBSD 9.4 |