linux/Documentation/sound/alsa/HD-Audio-Controls.txt
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   1This file explains the codec-specific mixer controls.
   2
   3Realtek codecs
   4--------------
   5
   6* Channel Mode
   7  This is an enum control to change the surround-channel setup,
   8  appears only when the surround channels are available.
   9  It gives the number of channels to be used, "2ch", "4ch", "6ch",
  10  and "8ch".  According to the configuration, this also controls the
  11  jack-retasking of multi-I/O jacks.
  12
  13* Auto-Mute Mode
  14  This is an enum control to change the auto-mute behavior of the
  15  headphone and line-out jacks.  If built-in speakers and headphone
  16  and/or line-out jacks are available on a machine, this controls
  17  appears.
  18  When there are only either headphones or line-out jacks, it gives
  19  "Disabled" and "Enabled" state.  When enabled, the speaker is muted
  20  automatically when a jack is plugged.
  21
  22  When both headphone and line-out jacks are present, it gives
  23  "Disabled", "Speaker Only" and "Line-Out+Speaker".  When
  24  speaker-only is chosen, plugging into a headphone or a line-out jack
  25  mutes the speakers, but not line-outs.  When line-out+speaker is
  26  selected, plugging to a headphone jack mutes both speakers and
  27  line-outs.
  28
  29
  30IDT/Sigmatel codecs
  31-------------------
  32
  33* Analog Loopback
  34  This control enables/disables the analog-loopback circuit.  This
  35  appears only when "loopback" is set to true in a codec hint
  36  (see HD-Audio.txt).  Note that on some codecs the analog-loopback
  37  and the normal PCM playback are exclusive, i.e. when this is on, you
  38  won't hear any PCM stream.
  39
  40* Swap Center/LFE
  41  Swaps the center and LFE channel order.  Normally, the left
  42  corresponds to the center and the right to the LFE.  When this is
  43  ON, the left to the LFE and the right to the center.
  44
  45* Headphone as Line Out
  46  When this control is ON, treat the headphone jacks as line-out
  47  jacks.  That is, the headphone won't auto-mute the other line-outs,
  48  and no HP-amp is set to the pins.
  49
  50* Mic Jack Mode, Line Jack Mode, etc
  51  These enum controls the direction and the bias of the input jack
  52  pins.  Depending on the jack type, it can set as "Mic In" and "Line 
  53  In", for determining the input bias, or it can be set to "Line Out"
  54  when the pin is a multi-I/O jack for surround channels.
  55
  56
  57VIA codecs
  58----------
  59
  60* Smart 5.1
  61  An enum control to re-task the multi-I/O jacks for surround outputs.
  62  When it's ON, the corresponding input jacks (usually a line-in and a
  63  mic-in) are switched as the surround and the CLFE output jacks.
  64
  65* Independent HP
  66  When this enum control is enabled, the headphone output is routed
  67  from an individual stream (the third PCM such as hw:0,2) instead of
  68  the primary stream.  In the case the headphone DAC is shared with a
  69  side or a CLFE-channel DAC, the DAC is switched to the headphone
  70  automatically.
  71
  72* Loopback Mixing
  73  An enum control to determine whether the analog-loopback route is
  74  enabled or not.  When it's enabled, the analog-loopback is mixed to
  75  the front-channel.  Also, the same route is used for the headphone
  76  and speaker outputs.  As a side-effect, when this mode is set, the
  77  individual volume controls will be no longer available for
  78  headphones and speakers because there is only one DAC connected to a
  79  mixer widget.
  80
  81* Dynamic Power-Control
  82  This control determines whether the dynamic power-control per jack
  83  detection is enabled or not.  When enabled, the widgets power state
  84  (D0/D3) are changed dynamically depending on the jack plugging
  85  state for saving power consumptions.  However, if your system
  86  doesn't provide a proper jack-detection, this won't work; in such a
  87  case, turn this control OFF.
  88
  89* Jack Detect
  90  This control is provided only for VT1708 codec which gives no proper
  91  unsolicited event per jack plug.  When this is on, the driver polls
  92  the jack detection so that the headphone auto-mute can work, while 
  93  turning this off would reduce the power consumption.
  94
  95
  96Conexant codecs
  97---------------
  98
  99* Auto-Mute Mode
 100  See Reatek codecs.
 101
 102
 103Analog codecs
 104--------------
 105
 106* Channel Mode
 107  This is an enum control to change the surround-channel setup,
 108  appears only when the surround channels are available.
 109  It gives the number of channels to be used, "2ch", "4ch" and "6ch".
 110  According to the configuration, this also controls the
 111  jack-retasking of multi-I/O jacks.
 112
 113* Independent HP
 114  When this enum control is enabled, the headphone output is routed
 115  from an individual stream (the third PCM such as hw:0,2) instead of
 116  the primary stream.
 117