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 <mfwitten@gmail.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/sound/drivers/Kconfig b/sound/drivers/Kconfig
index 84714a65e5c81a0a777577cc78ce115f4f3a99c2..32646000ab90460dd3525dc934a49071adf552d5 100644 (file)
--- 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.
 
 config SND_AC97_POWER_SAVE_DEFAULT
        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.
+
 endif  # SND_DRIVERS