[ALSA] Add experimental support of aggressive AC97 power-saving mode
Added CONFIG_SND_AC97_POWER_SAVE kernel config to enable the support
of aggressive AC97 power-saving mode. In this mode, the AC97
powerdown register bits are dynamically controlled at each open/close
of PCM streams.
The mode is activated via power_save option for snd-ac97-codec
driver. As default it's off. It can be turned on/off on the fly
via sysfs, too.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@suse.cz>
diff --git a/sound/pci/via82xx.c b/sound/pci/via82xx.c
index 08da923..2c23a66 100644
--- a/sound/pci/via82xx.c
+++ b/sound/pci/via82xx.c
@@ -1277,7 +1277,18 @@
if (! ratep->used)
ratep->rate = 0;
spin_unlock_irq(&ratep->lock);
-
+ if (! ratep->rate) {
+ if (! viadev->direction) {
+ snd_ac97_update_power(chip->ac97,
+ AC97_PCM_FRONT_DAC_RATE, 0);
+ snd_ac97_update_power(chip->ac97,
+ AC97_PCM_SURR_DAC_RATE, 0);
+ snd_ac97_update_power(chip->ac97,
+ AC97_PCM_LFE_DAC_RATE, 0);
+ } else
+ snd_ac97_update_power(chip->ac97,
+ AC97_PCM_LR_ADC_RATE, 0);
+ }
viadev->substream = NULL;
return 0;
}
