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SND_HDA(4)		 BSD Kernel Interfaces Manual		    SND_HDA(4)

     snd_hda --	Intel High Definition Audio bridge device driver

     kernel configuration file:

	   device sound
	   device snd_hda

     following line in loader.conf(5):


     The High Definition (HD) Audio specification was developed	by Intel as
     the logical successor of the old AC'97 specification and has several ad-
     vantages, such as higher bandwidth	which allows more channels and more
     detailed formats, support for several logical audio devices, and general
     purpose DMA channels.

     The snd_hda driver	includes HDA bus controller driver (hdac), HDA codec
     driver (hdacc) and	HDA codecs audio functions bridge driver (hdaa)	that
     allows the	generic	audio driver, sound(4),	to be used with	this hardware.
     Only audio	functions are supported	by snd_hda.  Modem and other possible
     functions are not implemented.

     The snd_hda driver	supports hardware that conforms	with revision 1.0 of
     the Intel High Definition Audio specification and tries to	behave much
     like the Microsoft	Universal Audio	Architecture (UAA) draft (revision
     0.7b) for handling	audio devices.

     According to HDA and UAA specifications, depending	on the number of HDA
     buses and codecs present in system, their audio capabilities and BIOS
     provided configuration, the snd_hda driver	often provides several PCM au-
     dio devices.  For example,	one device for main rear 7.1 output and	in-
     puts, one device for independent headset connectors at front and one de-
     vice for SPDIF or HDMI audio input/output.	 The assignment	of audio in-
     puts and outputs may be tuned with	device.hints(5)	or sysctl(8).  The
     driver's verbose boot messages provide a lot of information about the op-
     eration of	the driver and present audio setup.

     The default audio device may be tuned by setting the hw.snd.default_unit
     sysctl, as	described in sound(4), or explicitly specified in application

   Boot-time Configuration
     The following variables are available at boot-time	through	the
     device.hints(5) file:

	   hint.hdac.%d.config	Configures a range of possible controller op-
				tions.	Possible values	are: "64bit",
				"dmapos", "msi".  An option prefixed with
				"no", such as "nomsi", will do the opposite
				and takes precedence.  Options can be sepa-
				rated by whitespace and	commas.

	   hint.hdac.%d.msi	Controls MSI (Message Signaled Interrupts)

				Same as	hint.hdaa.%d.nid%d.config

	   hint.hdaa.%d.config	Configures a range of possible audio function
				options.  Possible values are: "eapdinv",
				"ivref", "ivref50", "ivref80", "ivref100",
				"fixedrate", "forcestereo", "ovref",
				"ovref50", "ovref80", "ovref100", "senseinv",
				"softpcmvol", and "vref".  An option prefixed
				with "no", such	as "nofixedrate", will do the
				opposite and takes precedence.	Options	can be
				separated by whitespace	and commas.

				The "eapdinv" option inverts External Ampli-
				fier Power Down	signal.	 The "fixedrate" de-
				nies all sampling rates	except 48KHz.  The
				"forcestereo" denies mono playback/recording.
				The "senseinv" option inverts jack sensing
				logic.	The "ivrefX" and "ovrefX" options con-
				trol the voltage used to power external	micro-

				Overrides audio	function GPIO pins configura-
				tion set by BIOS.  May be specified as a set
				of space-separated "num=value" pairs, where
				num is GPIO line number, and value is one of:
				"keep",	"set", "clear",	"disable" and "input".

				"GPIOs"	are a codec's General Purpose I/O pins
				which system integrators sometimes use to con-
				trol external muters, amplifiers and so	on.
				If you have no sound, or sound volume is not
				adequate, you may have to experiment a bit
				with the GPIO setup to find the	optimal	setup
				for your system.

				Overrides audio	function pin configuration set
				by BIOS.  May be specified as a	32-bit hexa-
				decimal	value with a leading "0x", or as a set
				of space-separated "option=value" pairs.

				Controls automatic recording source feature:
				0   disabled,
				1   once on attach,
				2   enabled.
				When enabled, driver will automatically	set
				recording source of the	mixer to connected in-
				put using jack presence	detection statuses.

     Pin configuration is the UAA driver's main	source of information about
     codec usage.  This	information is usually provided	by the codec manufac-
     turer and tuned by	system integrators for specific	system requirements.
     The snd_hda driver	allows users to	override it to fix integrator mistakes
     or	to use the available codec in alternative ways (for example to get
     stereo output and 2 inputs	instead	of a single 5.1	output).

     The following options are supported:

	   as	    Association	number.	 Associations are used to group	indi-
		    vidual pins	to form	a complex multi-pin device.  For exam-
		    ple, to group 4 connectors for 7.1 input/output, or	to
		    treat several input	connectors as sources for the same in-
		    put	device.	 Association numbers can be specified as nu-
		    meric values from 0	to 15.	A value	of 0 means disabled
		    pin.  A value of 15	is a set of independent	unassociated
		    pins.  Each	association includes only pins of the same di-
		    rection (in/out) and is detected atomically	(all pins or
		    none).  A separate PCM audio device	is created for every
		    pair of input and output associations.

	   seq	    Sequence number.  A	unique,	per-association	number used to
		    order pins inside the particular association.  Sequence
		    numbers can	be specified as	numeric	values from 0 to 15.

		    The	sequence number	15 has a special meaning for output
		    associations.  Output pins with this number	and device
		    type "Headphones" will duplicate (with automatic mute if
		    jack detection is supported) the first pin in that associ-

		    The	sequence numbers 14 and	15 has a special meaning for
		    input associations.	 Their presence	in association defines
		    it as multiplexed or mixed respectively.  If none of them
		    are	present	and there are more than	one pin	in associa-
		    tion, the association will provide multichannel input.

		    For	multichannel input/output associations sequence	num-
		    bers encode	channel	pairs positions: 0 - Front, 1 -	Cen-
		    ter/LFE, 2 - Back, 3 - Front Wide Center, 4	- Side.	 Stan-
		    dard combinations are: (0) - Stereo; (0, 2), (0, 4)	-
		    Quadro; (0,	1, 2), (0, 1, 4) - 5.1;	(0, 1, 2, 4) - 7.1.

	   device   Device type.  Can be specified as a	number from 0 to 15 or
		    as a name: "Line-out", "Speaker", "Headphones," "CD",
		    "SPDIF-out", "Digital-out",	"Modem-line", "Modem-handset",
		    "Line-in", "AUX", "Mic", "Telephony", "SPDIF-in",
		    "Digital-in", "Res.E", or "Other".	The device type	also
		    describes the pin direction	(in/out).  For example,	"CD"
		    always means an input pin, while "Headphones" always means
		    an output.

	   conn	    Connection type.  Can be specified as a number from	0 to
		    3.	The connection type can	also be	specified as one of
		    the	special	names "Jack", "None", "Fixed", or "Both".
		    Pins with a	connection type	of "None" are disabled.

	   ctype    Connector physical type.  Can be specified as a number
		    from 0 to 15.  This	is a reference only value.  It is ig-
		    nored by the snd_hda driver.

	   color    Connector color.  Can be specified as a number from	0 to
		    15 or as one of the	names "Unknown", "Black", "Grey",
		    "Blue", "Green", "Red", "Orange", "Yellow",	"Purple",
		    "Pink", "Res.A", "Res.B", "Res.C", "Res.D",	"White", or
		    "Other".  This is a	reference only value.  It is ignored
		    by the snd_hda driver.

	   loc	    Connector physical location.  Can be specified as a	number
		    from 0 to 63.  This	is a reference only value.  It is ig-
		    nored by the snd_hda driver.

	   misc	    Misc bits.	Can be specified as a number from 0 to 15.
		    Bit	0 has a	special	meaning.  When set it means that jack
		    detection is not implemented in hardware.

   Runtime Configuration
     The following sysctl(8) variables are available in	addition to those
     available to all sound(4) devices:

	   dev.hdac.%d.pindump	       Setting this to a non-zero value	dumps
				       the current pin configuration, main ca-
				       pabilities and jack sense status	of all
				       audio functions on the controller to
				       console and syslog.

	   dev.hdac.%d.polling	       Enables polling mode.  In this mode the
				       driver operates by querying the device
				       state on	timer ticks using callout(9)
				       instead of interrupts.  Polling is dis-
				       abled by	default.  Do not enable	it un-
				       less you	are facing weird interrupt
				       problems	or if the device cannot	gener-
				       ate interrupts at all.

	   dev.hdaa.%d.config	       Run-time	equivalent of the
				       hint.hdaa.%d.config tunable.

	   dev.hdaa.%d.gpi_state       Current state of	GPI lines.

	   dev.hdaa.%d.gpio_state      Current state of	GPIO lines.

	   dev.hdaa.%d.gpio_config     Run-time	equivalent of the
				       hint.hdaa.%d.gpio.config	tunable.

	   dev.hdaa.%d.gpo_state       Current state of	GPO lines.

	   dev.hdaa.%d.nid%d_config    Run-time	equivalent of the
				       hint.hdaa.%d.nid%d.config tunable.

	   dev.hdaa.%d.nid%d_original  Original	pin configuration written by

	   dev.hdaa.%d.reconfig	       Setting this to a non-zero value	makes
				       driver to destroy existing pcm devices
				       and process new pins configuration set
				       via dev.hdaa.%d.nid%d_config., dev.pcm.%d.rec.32bit
				       HDA controller uses 32bit representa-
				       tion for	all samples of more then 16
				       bits.  These variables allow to specify
				       how many	bits of	these 32 should	be
				       used by CODEC.  Depending on codec ca-
				       pabilities, possible values are 20, 24
				       and 32 bit.  The	default	value is 24.

	   dev.pcm.%d.rec.autosrc      Run-time	equivalent of the
				       hint.pcm.%d.rec.autosrc tunable.

     Taking HP Compaq DX2300 with Realtek ALC888 HDA codec for example.	 This
     system has	two audio connectors on	a front	side, three audio connectors
     on	a rear side and	one internal speaker.  According to verbose driver
     output and	the codec datasheet, this codec	has five stereo	DACs and two
     stereo ADCs, all of them are routable to any codec	pin (external connec-
     tor).  All	codec pins are reversible (could be configured either as input
     or	output).

     So	high codec uniformity and flexibility allow driver to configure	it in
     many different ways, depending on requested pins usage described by pins
     configuration.  The driver	reports	such default pin configuration when
     verbose messages enabled:

     hdaa0: nid	  0x	as seq device	    conn  jack	  loc	     color   misc
     hdaa0: 20 01014020	2  0  Line-out	    Jack  1/8	  Rear	     Green   0
     hdaa0: 21 99130110	1  0  Speaker	    Fixed ATAPI	  Onboard    Unknown 1
     hdaa0: 22 411111f0	15 0  Speaker	    None  1/8	  Rear	     Black   1 DISA
     hdaa0: 23 411111f0	15 0  Speaker	    None  1/8	  Rear	     Black   1 DISA
     hdaa0: 24 01a19830	3  0  Mic	    Jack  1/8	  Rear	     Pink    8
     hdaa0: 25 02a1983f	3  15 Mic	    Jack  1/8	  Front	     Pink    8
     hdaa0: 26 01813031	3  1  Line-in	    Jack  1/8	  Rear	     Blue    0
     hdaa0: 27 0221401f	1  15 Headphones    Jack  1/8	  Front	     Green   0
     hdaa0: 28 411111f0	15 0  Speaker	    None  1/8	  Rear	     Black   1 DISA
     hdaa0: 30 411111f0	15 0  Speaker	    None  1/8	  Rear	     Black   1 DISA
     hdaa0: 31 411111f0	15 0  Speaker	    None  1/8	  Rear	     Black   1 DISA

     Here we can see, that the nodes with ID (nid) 25 and 27 are front panel
     connectors	(Jack, Front), nids 20,	24 and 26 are rear panel connectors
     (Jack, Rear) and nid 21 is	a built-in speaker (Fixed, Onboard).  Pins
     with nids 22, 23, 28, 30 and 31 will be disabled by driver	due to "None"
     connectivity.  So the pin count and description matches to	connectors
     that we have.

     Using association (as) and	sequence (seq) fields values pins are grouped
     into 3 associations:

     hdaa0: Association	0 (1) out:
     hdaa0:   Pin nid=21 seq=0
     hdaa0:   Pin nid=27 seq=15
     hdaa0: Association	1 (2) out:
     hdaa0:   Pin nid=20 seq=0
     hdaa0: Association	2 (3) in:
     hdaa0:   Pin nid=24 seq=0
     hdaa0:   Pin nid=26 seq=1
     hdaa0:   Pin nid=25 seq=15

     Each pcm(4) device	uses two associations: one for playback	and one	for
     recording.	 Associations processed	and assigned to	pcm(4) devices in in-
     creasing numerical	order.	In this	case association #0 (1)	will become
     pcm0 device playback, using the internal speakers and Headphones jack
     with speaker automute on the headphones jack connection.  Association #1
     (2) will become pcm1 playback, using the Line-out jack.  Association #2
     (3) will become pcm0 recording, using the external	microphones and	the
     Line-in jack.

     The snd_hda driver	provides extensive verbose messages to diagnose	its
     operation logic and describe its current codec configuration.

     Using device.hints(5) it is possible to modify the	configuration of the
     existing pins, allowing a broad range of different	audio setups.  Here
     are a few examples	of some	setups possible	for this particular hardware:

   Example 1
     Setting the device.hints(5) options


     will swap line-out	and speaker functions.	So the pcm0 device will	play
     to	the line-out and headphones jacks.  Line-out will be muted on the
     headphones	jack connection.  Recording on pcm0 will go from two external
     microphones and line-in jacks.  pcm1 playback will	go to the internal

   Example 2
     Setting the device.hints(5) options

     hint.hdac.0.cad0.nid20.config="as=1 seq=15	device=Headphones"
     hint.hdac.0.cad0.nid27.config="as=2 seq=0"
     hint.hdac.0.cad0.nid25.config="as=4 seq=0"

     will split	the headphones and one of the microphones to a separate	de-
     vice.  The	pcm0 device will play to the internal speaker and to the line-
     out jack, with speaker automute on	the line-out jack connection.  Record-
     ing on pcm0 will use input	from one external microphone and the line-in
     jacks.  The pcm1 device will be completely	dedicated to a headset (head-
     phones and	mic) connected to the front connectors.

   Example 3
     Setting the device.hints(5) options

     hint.hdac.0.cad0.nid20.config="as=1 seq=0"
     hint.hdac.0.cad0.nid26.config="as=2 seq=0"
     hint.hdac.0.cad0.nid27.config="as=3 seq=0"
     hint.hdac.0.cad0.nid24.config="as=5 seq=0 device=Line-out"
     hint.hdac.0.cad0.nid21.config="as=6 seq=0"

     will give 4 independent devices: pcm0 (line-out and line-in), pcm1
     (headphones and mic), pcm2	(additional line-out via retasked rear mic
     jack), and	pcm3 (internal speaker).

   Example 4
     Setting the device.hints(5) options

     hint.hdac.0.cad0.nid24.config="as=1 seq=1 device=Line-out"
     hint.hdac.0.cad0.nid26.config="as=1 seq=2 device=Line-out"
     hint.hdac.0.cad0.nid21.config="as=2 seq=0"

     will give 2 devices: pcm0 for 5.1 playback	via 3 rear connectors (line-
     out and retasked mic and line-in) and headset (headphones and mic)	at
     front connectors.	pcm1 for internal speaker playback.  On	headphones
     connection	rear connectors	will be	muted.

     Depending on codec	configuration, these controls and signal sources could
     be	reported to sound(4):

	   vol	    overall output level (volume)

	   rec	    overall recording level

	   igain    input-to-output monitoring loopback	level

	   ogain    external amplifier control

	   pcm	    PCM	playback

	   mix	    input mix

	   mic	    first external or second internal microphone input

	   monitor  first internal or second external microphone input

	   line, line1,	line2, line3
		    analog (line) inputs

	   dig1, dig2, dig3
		    digital (S/PDIF, HDMI or DisplayPort) inputs

	   cd	    CD input

	   speaker  PC speaker input

	   phin, phout,	radio, video
		    other random inputs

     Controls have different precision.	 Some could be just an on/off trig-
     gers.  Most of controls use logarithmic scale.

     The snd_hda driver	supports controllers having PCI	class 4	(multimedia)
     and subclass 3 (HDA), compatible with Intel HDA specification.

     The snd_hda driver	supports more than two hundred different controllers
     and CODECs.  There	is no sense to list all	of them	here, as in most cases
     specific CODEC configuration and wiring are more important	then type of
     the CODEC itself.

     snd_ich(4), sound(4), device.hints(5), loader.conf(5), sysctl(8)

     The snd_hda device	driver first appeared in FreeBSD 6.3.

     The snd_hda driver	was written by Stephane	E. Potvin
     <>, Ariff Abdullah <> and Alexander
     Motin <>.  This manual page	was written by Joel Dahl
     <>, Alexander Motin <> and Giorgos
     Keramidas <>.

     Some Hardware/OEM vendors tend to screw up	BIOS settings or use custom
     unusual CODEC wiring that create problems to the driver.  This may	result
     in	missing	pcm devices, or	a state	where the snd_hda driver seems to at-
     tach and work, but	no sound is played.  Some cases	can be solved by tun-
     ing loader.conf variables.	 But before trying to fix problem that way,
     make sure that there really is a problem and that the PCM audio device in
     use really	corresponds to the expected audio connector.

     Some vendors use non-standardized General Purpose I/O (GPIO) pins of the
     codec to control external amplifiers.  In some cases setting a combina-
     tion of GPIO bits may be needed to	make sound work	on a specific device.

     HDMI and DisplayPort audio	may also require support from video driver.

BSD				 April 1, 2018				   BSD


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