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[ALSA] Add experimental support of aggressive AC97 power-saving mode

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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>
This commit is contained in:
Takashi Iwai
2006-06-27 18:28:53 +02:00
committed by Jaroslav Kysela
parent 2b29b13c57
commit 6dbe662874
6 changed files with 315 additions and 39 deletions
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18
sound/pci/ac97/ac97_pcm.c
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@@ -269,6 +269,7 @@ int snd_ac97_set_rate(struct snd_ac97 *ac97, int reg, unsigned int rate)
return -EINVAL;
}
snd_ac97_update_power(ac97, reg, 1);
switch (reg) {
case AC97_PCM_MIC_ADC_RATE:
if ((ac97->regs[AC97_EXTENDED_STATUS] & AC97_EA_VRM) == 0) /* MIC VRA */
@@ -606,6 +607,7 @@ int snd_ac97_pcm_open(struct ac97_pcm *pcm, unsigned int rate,
goto error;
}
}
pcm->cur_dbl = r;
spin_unlock_irq(&pcm->bus->bus_lock);
for (i = 3; i < 12; i++) {
if (!(slots & (1 << i)))
@@ -651,6 +653,21 @@ int snd_ac97_pcm_close(struct ac97_pcm *pcm)
unsigned short slots = pcm->aslots;
int i, cidx;
#ifdef CONFIG_SND_AC97_POWER_SAVE
int r = pcm->cur_dbl;
for (i = 3; i < 12; i++) {
if (!(slots & (1 << i)))
continue;
for (cidx = 0; cidx < 4; cidx++) {
if (pcm->r[r].rslots[cidx] & (1 << i)) {
int reg = get_slot_reg(pcm, cidx, i, r);
snd_ac97_update_power(pcm->r[r].codec[cidx],
reg, 0);
}
}
}
#endif
bus = pcm->bus;
spin_lock_irq(&pcm->bus->bus_lock);
for (i = 3; i < 12; i++) {
@@ -660,6 +677,7 @@ int snd_ac97_pcm_close(struct ac97_pcm *pcm)
bus->used_slots[pcm->stream][cidx] &= ~(1 << i);
}
pcm->aslots = 0;
pcm->cur_dbl = 0;
spin_unlock_irq(&pcm->bus->bus_lock);
return 0;
}