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ALSA: doc: ReSTize powersave document 

A simple conversion from a text file.
Put into designs subdirectory, although it's mostly relevant with
HD-audio.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Takashi Iwai 2016-11-09 15:54:47 +01:00
parent afb8fd3c72
commit 48e92b488d
2 changed files with 10 additions and 7 deletions
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1
Documentation/sound/designs/index.rst
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@ -5,3 +5,4 @@ Designs and Implementations
:maxdepth: 2
procfile
powersave

16
Documentation/sound/alsa/powersave.txt → Documentation/sound/designs/powersave.rst
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@ -1,9 +1,10 @@
==========================
Notes on Power-Saving Mode
==========================
AC97 and HD-audio drivers have the automatic power-saving mode.
This feature is enabled via Kconfig CONFIG_SND_AC97_POWER_SAVE
and CONFIG_SND_HDA_POWER_SAVE options, respectively.
This feature is enabled via Kconfig ``CONFIG_SND_AC97_POWER_SAVE``
and ``CONFIG_SND_HDA_POWER_SAVE`` options, respectively.
With the automatic power-saving, the driver turns off the codec power
appropriately when no operation is required. When no applications use
@ -11,20 +12,21 @@ the device and/or no analog loopback is set, the power disablement is
done fully or partially. It'll save a certain power consumption, thus
good for laptops (even for desktops).
The time-out for automatic power-off can be specified via power_save
The time-out for automatic power-off can be specified via ``power_save``
module option of snd-ac97-codec and snd-hda-intel modules. Specify
the time-out value in seconds. 0 means to disable the automatic
power-saving. The default value of timeout is given via
CONFIG_SND_AC97_POWER_SAVE_DEFAULT and
CONFIG_SND_HDA_POWER_SAVE_DEFAULT Kconfig options. Setting this to 1
``CONFIG_SND_AC97_POWER_SAVE_DEFAULT`` and
``CONFIG_SND_HDA_POWER_SAVE_DEFAULT`` Kconfig options. Setting this to 1
(the minimum value) isn't recommended because many applications try to
reopen the device frequently. 10 would be a good choice for normal
operations.
The power_save option is exported as writable. This means you can
The ``power_save`` option is exported as writable. This means you can
adjust the value via sysfs on the fly. For example, to turn on the
automatic power-save mode with 10 seconds, write to
/sys/modules/snd_ac97_codec/parameters/power_save (usually as root):
``/sys/modules/snd_ac97_codec/parameters/power_save`` (usually as root):
::
# echo 10 > /sys/modules/snd_ac97_codec/parameters/power_save