diff options
Diffstat (limited to 'Documentation/sound')
| -rw-r--r-- | Documentation/sound/designs/index.rst | 1 | ||||
| -rw-r--r-- | Documentation/sound/designs/powersave.rst (renamed from Documentation/sound/alsa/powersave.txt) | 16 |
2 files changed, 10 insertions, 7 deletions
diff --git a/Documentation/sound/designs/index.rst b/Documentation/sound/designs/index.rst index 82d19fe3c380..362e1c23d51f 100644 --- a/Documentation/sound/designs/index.rst +++ b/Documentation/sound/designs/index.rst @@ -5,3 +5,4 @@ Designs and Implementations :maxdepth: 2 procfile + powersave diff --git a/Documentation/sound/alsa/powersave.txt b/Documentation/sound/designs/powersave.rst index 9657e8099228..138157452eb9 100644 --- a/Documentation/sound/alsa/powersave.txt +++ b/Documentation/sound/designs/powersave.rst @@ -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 |