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