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authorTakashi Iwai <tiwai@suse.de>2011-07-19 09:34:10 +0200
committerTakashi Iwai <tiwai@suse.de>2011-07-19 09:34:10 +0200
commit737c265bb8399b97231e5b10b5b2375914206427 (patch)
tree5b556cb207d44947b8ba7b4a262e9116409577f5 /Documentation/sound
parent3b607e3d3a2538e06686c8c26057f95471ac1f9c (diff)
ALSA: hda - Add documentation for codec-specific mixer controls
Signed-off-by: Takashi Iwai <tiwai@suse.de>
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+This file explains the codec-specific mixer controls.
+
+Realtek codecs
+--------------
+
+* Channel Mode
+ This is an enum control to change the surround-channel setup,
+ appears only when the surround channels are available.
+ It gives the number of channels to be used, "2ch", "4ch", "6ch",
+ and "8ch". According to the configuration, this also controls the
+ jack-retasking of multi-I/O jacks.
+
+* Auto-Mute Mode
+ This is an enum control to change the auto-mute behavior of the
+ headphone and line-out jacks. If built-in speakers and headphone
+ and/or line-out jacks are available on a machine, this controls
+ appears.
+ When there are only either headphones or line-out jacks, it gives
+ "Disabled" and "Enabled" state. When enabled, the speaker is muted
+ automatically when a jack is plugged.
+
+ When both headphone and line-out jacks are present, it gives
+ "Disabled", "Speaker Only" and "Line-Out+Speaker". When
+ speaker-only is chosen, plugging into a headphone or a line-out jack
+ mutes the speakers, but not line-outs. When line-out+speaker is
+ selected, plugging to a headphone jack mutes both speakers and
+ line-outs.
+
+
+IDT/Sigmatel codecs
+-------------------
+
+* Analog Loopback
+ This control enables/disables the analog-loopback circuit. This
+ appears only when "loopback" is set to true in a codec hint
+ (see HD-Audio.txt). Note that on some codecs the analog-loopback
+ and the normal PCM playback are exclusive, i.e. when this is on, you
+ won't hear any PCM stream.
+
+* Swap Center/LFE
+ Swaps the center and LFE channel order. Normally, the left
+ corresponds to the center and the right to the LFE. When this is
+ ON, the left to the LFE and the right to the center.
+
+* Headphone as Line Out
+ When this control is ON, treat the headphone jacks as line-out
+ jacks. That is, the headphone won't auto-mute the other line-outs,
+ and no HP-amp is set to the pins.
+
+* Mic Jack Mode, Line Jack Mode, etc
+ These enum controls the direction and the bias of the input jack
+ pins. Depending on the jack type, it can set as "Mic In" and "Line
+ In", for determining the input bias, or it can be set to "Line Out"
+ when the pin is a multi-I/O jack for surround channels.
+
+
+VIA codecs
+----------
+
+* Smart 5.1
+ An enum control to re-task the multi-I/O jacks for surround outputs.
+ When it's ON, the corresponding input jacks (usually a line-in and a
+ mic-in) are switched as the surround and the CLFE output jacks.
+
+* Independent HP
+ When this enum control is enabled, the headphone output is routed
+ from an individual stream (the third PCM such as hw:0,2) instead of
+ the primary stream. In the case the headphone DAC is shared with a
+ side or a CLFE-channel DAC, the DAC is switched to the headphone
+ automatically.
+
+* Loopback Mixing
+ An enum control to determine whether the analog-loopback route is
+ enabled or not. When it's enabled, the analog-loopback is mixed to
+ the front-channel. Also, the same route is used for the headphone
+ and speaker outputs. As a side-effect, when this mode is set, the
+ individual volume controls will be no longer available for
+ headphones and speakers because there is only one DAC connected to a
+ mixer widget.
+
+* Dynamic Power-Control
+ This control determines whether the dynamic power-control per jack
+ detection is enabled or not. When enabled, the widgets power state
+ (D0/D3) are changed dynamically depending on the jack plugging
+ state for saving power consumptions. However, if your system
+ doesn't provide a proper jack-detection, this won't work; in such a
+ case, turn this control OFF.
+
+* Jack Detect
+ This control is provided only for VT1708 codec which gives no proper
+ unsolicited event per jack plug. When this is on, the driver polls
+ the jack detection so that the headphone auto-mute can work, while
+ turning this off would reduce the power consumption.
+
+
+Conexant codecs
+---------------
+
+* Auto-Mute Mode
+ See Reatek codecs.