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Diffstat (limited to 'Documentation/sound/alsa/powersave.txt')
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diff --git a/Documentation/sound/alsa/powersave.txt b/Documentation/sound/alsa/powersave.txt deleted file mode 100644 index 9657e8099228..000000000000 --- a/Documentation/sound/alsa/powersave.txt +++ /dev/null @@ -1,41 +0,0 @@ -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. - -With the automatic power-saving, the driver turns off the codec power -appropriately when no operation is required. When no applications use -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 -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 -(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 -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): - - # echo 10 > /sys/modules/snd_ac97_codec/parameters/power_save - - -Note that you might hear click noise/pop when changing the power -state. Also, it often takes certain time to wake up from the -power-down to the active state. These are often hardly to fix, so -don't report extra bug reports unless you have a fix patch ;-) - -For HD-audio interface, there is another module option, -power_save_controller. This enables/disables the power-save mode of -the controller side. Setting this on may reduce a bit more power -consumption, but might result in longer wake-up time and click noise. -Try to turn it off when you experience such a thing too often. |