AZALIA(4)                 OpenBSD Programmer's Manual                AZALIA(4)

NAME
     azalia - generic High Definition Audio device

SYNOPSIS
     azalia* at pci?
     audio* at azalia?

DESCRIPTION
     The azalia device driver is expected to support any PCI device which is
     compliant with the High Definition Audio Specification 1.0.

     Supported controllers include:

           o   Acer Labs M5461
           o   ATI SB450, SB600, SB700, SB800
           o   Intel 82801FB/GB/H/I/JI (ICH6, ICH7, ICH8, ICH9, ICH10)
           o   NVIDIA MCP51/MCP55/MCP61/MCP65/MCP67/MCP73/MCP77/MCP79/MCP89
           o   Silicon Integrated System 966/966L
           o   VIA Technologies VT8237A, VT8251

     The High Definition Audio (HDA) specification describes a flexible and
     extensible infrastructure to support high quality audio.  HDA supports
     sample rates up to 192 kHz, bit rates of up to 32 bits per sample, and up
     to 16 channels in audio streams.  It also supports S/PDIF input/output as
     well as jack retasking and sensing.  The HDA specification defines a con-
     troller register set and a codec architecture.

MIXER INTERFACE
     The codec is the main audio processor.  Configuration of the device, such
     as selecting playback sample rate or decreasing the volume, is handled by
     the codec.  Codecs are comprised of interconnected widgets.  Common exam-
     ples of widgets include DACs (digital to analog converter), ADCs (analog
     to digital converter), selectors, mixers, and pin complexes (input/output
     jacks).  Widgets may have fixed or controllable properties.  Some of
     these properties include source selection, amplifier gain, mute, and op-
     erational direction.

     The mixer interface for azalia is designed to allow the user to control
     most properties of the widgets.  When azalia first attaches and config-
     ures the device, it will set all widgets to unmuted, moderate volume, and
     configure connections such that stereo playback and recording will work
     with the expected input/output pins.

     There are a wide range of HDA codecs.  Some have only a few widgets that
     don't have many controllable properties, and some may have many, very
     controllable widgets.  The mixer interface on one azalia may be very dif-
     ferent than the mixer interface on another.

     Mixer item names describe the widget and property being controlled.
     Names take the following form:

     <mixer class>.<widget type>[<widget type enumerator>][_<property>]

     The mixer class gives a hint as to the purpose of the control.  The wid-
     get type enumerator is used to distinguish different widgets of the same
     type.  The enumeration starts at 2: the first widget of each type is not
     enumerated.  The enumeration order is meaningless.  The property is op-
     tional.  Generally, if there is no property, the mixer item is an ampli-
     fier gain control.

     The following are the widget type names used in mixer control names:

     dac       Digital to analog converter, usually used for playback.  The
               audio stream channels these widgets will convert are encoded
               into their name in the form of <start channel>:<end channel>.
               For example, dac-0:1 converts channels 0 and 1 (stereo).  How-
               ever, a dac that is connected to built-in speakers or front
               panel headphone jacks by default will convert audio stream
               channels starting at 0 if the dac would otherwise not be con-
               verting any channels.  For example, if dac-2:3 is the default
               dac for the built-in speakers in a laptop, dac-2:3 will convert
               channels 0 and 1 when a stereo audio stream is being played.
               This is to allow simultaneous stereo playback on both the
               built-in speakers and a line or headphone jack.

     dig-dac   Digital output converter, usually an S/PDIF transmitter.  The
               audio stream channels these widgets will convert are encoded
               into their name in the form of <start channel>:<end channel>.
               For example, dig-dac-0:1 converts channels 0 and 1 (stereo).

     adc       Analog to digital converter, usually used for recording.  The
               audio stream channels these widgets will convert are encoded
               into their name in the form of <start channel>:<end channel>.
               For example, adc-0:1 converts channels 0 and 1 (stereo).

     dig-adc   Digital input converter, usually an S/PDIF receiver.  The audio
               stream channels these widgets will convert are encoded into
               their name in the form of <start channel>:<end channel>.  For
               example, dig-adc-0:1 converts channels 0 and 1 (stereo).

     mix       Sums multiple audio sources into a single stream, but sometimes
               only used for amplifier or mute properties.  The property part
               of a mix widget mixer control name may be the name of another
               widget.  Such a mixer item controls the input level from the
               widget in the property part of the name.

     sel       Selects a single audio source, but sometimes used only for am-
               plifier or mute properties.

     pow       Controls power state for a group of widgets.

     volume    Interprets data from external controls, such as a volume knob.

     beep      Creates a tone at a certain frequency.

     line      Pin complex for a line-level jack that is normally used for
               analog audio output.  The name may also be appended with a col-
               or abbreviation such as -grn (green), -blk (black), -org (or-
               ange), or -gry (grey), to help differentiate jacks.

     spkr      Pin complex for a speaker, often built into the machine.

     hp        Pin complex for a jack that is normally used for output to a
               headphone.

     cd        Pin complex for analog audio input from a CD device.

     SPDIF     Pin complex for an S/PDIF output connector.

     line-in   Pin complex for a line-level jack that is normally used for
               analog audio input.

     aux       Pin complex for an auxiliary analog audio input.

     mic       Pin complex for analog audio input from a microphone, either a
               jack or built into the machine.

     SPDIF-in  Pin complex for an S/PDIF input connector.

     beep      Pin complex for analog audio input from a beep generator.

     The following are the property names used in mixer control names:

     mute    Mutes input or output audio stream.

     source  Selects input source.  Can either select a single source or mul-
             tiple sources.  Sometimes these controls may only have a single
             choice, but they are provided to show how audio streams move
             through the codec.

     dir     Selects pin direction and input VRef signal.  VRef is represented
             in percent of the analog voltage rail.  For example, 'input-vr80'
             means input direction with 80% VRef.

     boost   Enables/disables low impedance amplifier, usually for use with
             headphones.

     eapd    Powers on/off external amplifier circuitry.

     sense   Reports current jack sense state.

     There are also some special mixer controls that don't directly correspond
     to properties of the widgets, but control aspects of the driver or other
     mixer controls.  The following describes these special controls:

     outputs.spkr_muters    List of pins that can mute a built-in speaker.  A
                            pin mutes the speaker by sending a signal when it
                            senses that something has been plugged into its
                            jack.  If a pin supports both input and output op-
                            eration, the pin will only mute the speaker when
                            plugged into if that pin is configured for output.

     outputs.master.slaves  List of widgets with amplifier gain or mute con-
                            trols that are configured with the parameters used
                            for outputs.master and outputs.master.mute.  For
                            example, if dac is in the list and has an input
                            amplifier gain control, setting outputs.master to
                            200 will set inputs.dac to 200.

     outputs.master         Amplifier gain control for widgets listed in
                            outputs.master.slaves.

     outputs.master.mute    Mute control for widgets listed in
                            outputs.master.slaves.

     record.volume.slaves   List of widgets with amplifier gain or mute con-
                            trols that are configured with the parameters used
                            for record.volume and record.volume.mute.  For ex-
                            ample, if adc is in the list and has an input am-
                            plifier gain control, setting record.volume to 200
                            will set record.adc to 200.

     record.volume          Amplifier gain control for widgets listed in
                            record.volume.slaves.

     record.volume.mute     Mute control for widgets listed in
                            record.volume.slaves.

     outputs.mode           Controls whether the digital or analog converters
                            and pins will be used for playback.

     record.mode            Controls whether the digital or analog converters
                            and pins will be used for recording.

SEE ALSO
     audio(4), pci(4)

HISTORY
     The azalia device driver first appeared in NetBSD 3.0.  OpenBSD support
     first appeared in OpenBSD 4.0.

BUGS
     This driver does not support codecs that are intended for HDMI or Dis-
     playPort connectivity.

OpenBSD 4.7                    November 25, 2009                             4
