path: root/sound/drivers
diff options
authorMichael Witten <>2010-07-14 23:54:21 +0000
committerTakashi Iwai <>2010-07-15 13:43:44 +0200
commit1d8c1100fbf956b9c5994077a4d3c6490c23e087 (patch)
tree6562aca545800135b7c334a465c3ff792552a5fb /sound/drivers
parent992cbf743862916dfbfdd3238fe3fecffbab5dd3 (diff)
ALSA: Kconfig: SND_AC97_POWER_SAVE description improvement
The description has been expanded to explain the time-out value provided by the power_save module parameter. Signed-off-by: Michael Witten <> Signed-off-by: Takashi Iwai <>
Diffstat (limited to 'sound/drivers')
1 files changed, 21 insertions, 3 deletions
diff --git a/sound/drivers/Kconfig b/sound/drivers/Kconfig
index 84714a65e5c8..32646000ab90 100644
--- a/sound/drivers/Kconfig
+++ b/sound/drivers/Kconfig
@@ -170,9 +170,25 @@ config SND_AC97_POWER_SAVE
AC97 codecs. In this mode, the power-mode is dynamically
controlled at each open/close.
- The mode is activated by passing power_save=1 option to
- snd-ac97-codec driver. You can toggle it dynamically over
- sysfs, too.
+ The mode is activated by passing 'power_save=X' to the
+ snd-ac97-codec driver module, where 'X' is the time-out
+ value, a nonnegative integer that specifies how many
+ seconds of idle time the driver must count before it may
+ put the AC97 into power-save mode; a value of 0 (zero)
+ disables the use of this power-save mode.
+ After the snd-ac97-codec driver module has been loaded,
+ the 'power_save' parameter can be set via sysfs as follows:
+ echo 10 > /sys/module/snd_ac97_codec/parameters/power_save
+ In this case, the time-out is set to 10 seconds; setting
+ the time-out to 1 second (the minimum activation value)
+ isn't recommended because many applications try to reopen
+ the device frequently. A value of 10 seconds would be a
+ good choice for normal operations.
+ See Documentation/sound/alsa/powersave.txt for more details.
int "Default time-out for AC97 power-save mode"
@@ -182,4 +198,6 @@ config SND_AC97_POWER_SAVE_DEFAULT
The default time-out value in seconds for AC97 automatic
power-save mode. 0 means to disable the power-save mode.
+ See SND_AC97_POWER_SAVE for more details.