[ALSA] hda-intel - Add POWER_SAVE option

Added CONFIG_SND_HDA_POWER_SAVE kconfig.  It's an experimental option
to achieve an aggressive power-saving.  With this option, the driver
will turn on/off the power of each codec and controller chip dynamically
on demand.
The patch introduces a new module option 'power_save'.  It specifies
the second of time-out for automatic power-down.  As default, it's
10 seconds.  Setting 0 means to suppress the power-saving feature.
The codec may have analog-input loopbacks, which are usually represented
by mixer elements such as 'Mic Playback Switch' or 'CD Playback Switch'.
When these are on, we cannot turn off the mixer and the codec chip has
to be kept on.  For bookkeeping these states, a new codec-callback is
introduced.
For the bus-controller side, a new callback pm_notify is introduced,
which can be used to turn on/off the contoller appropriately.
Note that this power-saving might cause slight click-noise at
power-on/off.  Also, it might take some time to wake up the codec, and
might even drop some tones at the very beginning.  This seems to be the
side-effect of turning off the controller chip.
This turn-off of the controller can be disabled by undefining
HDA_POWER_SAVE_RESET_CONTOLLER in hda_intel.c.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@suse.cz>

1 files changed, 123 insertions, 35 deletions

diff --git a/sound/pci/hda/hda_intel.c b/sound/pci/hda/hda_intel.c
index ebb442dcc027..7be3a9b55330 100644
--- a/sound/pci/hda/hda_intel.c
+++ b/sound/pci/hda/hda_intel.c
@@ -75,6 +75,7 @@ MODULE_PARM_DESC(single_cmd, "Use single command to communicate with codecs "
 module_param(enable_msi, int, 0);
 MODULE_PARM_DESC(enable_msi, "Enable Message Signaled Interrupt (MSI)");
 
+/* power_save option is defined in hda_codec.c */
 
 /* just for backward compatibility */
 static int enable;
@@ -102,6 +103,18 @@ MODULE_DESCRIPTION("Intel HDA driver");
 #define SFX	"hda-intel: "
 
 /*
+ * build flags
+ */
+
+/*
+ * reset the HD-audio controller in power save mode.
+ * this may give more power-saving, but will take longer time to
+ * wake up.
+ */
+#define HDA_POWER_SAVE_RESET_CONTROLLER
+
+
+/*
  * registers
  */
 #define ICH6_REG_GCAP			0x00
@@ -345,6 +358,7 @@ struct azx {
 
 	/* flags */
 	int position_fix;
+	unsigned int running :1;
 	unsigned int initialized :1;
 	unsigned int single_cmd :1;
 	unsigned int polling_mode :1;
@@ -665,6 +679,9 @@ static unsigned int azx_get_response(struct hda_codec *codec)
 		return azx_rirb_get_response(codec);
 }
 
+#ifdef CONFIG_SND_HDA_POWER_SAVE
+static void azx_power_notify(struct hda_codec *codec);
+#endif
 
 /* reset codec link */
 static int azx_reset(struct azx *chip)
@@ -790,19 +807,12 @@ static void azx_stream_stop(struct azx *chip, struct azx_dev *azx_dev)
 
 
 /*
- * initialize the chip
+ * reset and start the controller registers
  */
 static void azx_init_chip(struct azx *chip)
 {
-	unsigned char reg;
-
-	/* Clear bits 0-2 of PCI register TCSEL (at offset 0x44)
-	 * TCSEL == Traffic Class Select Register, which sets PCI express QOS
-	 * Ensuring these bits are 0 clears playback static on some HD Audio
-	 * codecs
-	 */
-	pci_read_config_byte (chip->pci, ICH6_PCIREG_TCSEL, &reg);
-	pci_write_config_byte(chip->pci, ICH6_PCIREG_TCSEL, reg & 0xf8);
+	if (chip->initialized)
+		return;
 
 	/* reset controller */
 	azx_reset(chip);
@@ -819,22 +829,45 @@ static void azx_init_chip(struct azx *chip)
 	azx_writel(chip, DPLBASE, (u32)chip->posbuf.addr);
 	azx_writel(chip, DPUBASE, upper_32bit(chip->posbuf.addr));
 
+	chip->initialized = 1;
+}
+
+/*
+ * initialize the PCI registers
+ */
+/* update bits in a PCI register byte */
+static void update_pci_byte(struct pci_dev *pci, unsigned int reg,
+			    unsigned char mask, unsigned char val)
+{
+	unsigned char data;
+
+	pci_read_config_byte(pci, reg, &data);
+	data &= ~mask;
+	data |= (val & mask);
+	pci_write_config_byte(pci, reg, data);
+}
+
+static void azx_init_pci(struct azx *chip)
+{
+	/* Clear bits 0-2 of PCI register TCSEL (at offset 0x44)
+	 * TCSEL == Traffic Class Select Register, which sets PCI express QOS
+	 * Ensuring these bits are 0 clears playback static on some HD Audio
+	 * codecs
+	 */
+	update_pci_byte(chip->pci, ICH6_PCIREG_TCSEL, 0x07, 0);
+
 	switch (chip->driver_type) {
 	case AZX_DRIVER_ATI:
 		/* For ATI SB450 azalia HD audio, we need to enable snoop */
-		pci_read_config_byte(chip->pci,
-				     ATI_SB450_HDAUDIO_MISC_CNTR2_ADDR, 
-				     &reg);
-		pci_write_config_byte(chip->pci,
-				      ATI_SB450_HDAUDIO_MISC_CNTR2_ADDR, 
-				      (reg & 0xf8) |
-				      ATI_SB450_HDAUDIO_ENABLE_SNOOP);
+		update_pci_byte(chip->pci,
+				ATI_SB450_HDAUDIO_MISC_CNTR2_ADDR, 
+				0x07, ATI_SB450_HDAUDIO_ENABLE_SNOOP);
 		break;
 	case AZX_DRIVER_NVIDIA:
 		/* For NVIDIA HDA, enable snoop */
-		pci_read_config_byte(chip->pci,NVIDIA_HDA_TRANSREG_ADDR, &reg);
-		pci_write_config_byte(chip->pci,NVIDIA_HDA_TRANSREG_ADDR,
-				      (reg & 0xf0) | NVIDIA_HDA_ENABLE_COHBITS);
+		update_pci_byte(chip->pci,
+				NVIDIA_HDA_TRANSREG_ADDR,
+				0x0f, NVIDIA_HDA_ENABLE_COHBITS);
 		break;
         }
 }
@@ -1007,6 +1040,9 @@ static int __devinit azx_codec_create(struct azx *chip, const char *model)
 	bus_temp.pci = chip->pci;
 	bus_temp.ops.command = azx_send_cmd;
 	bus_temp.ops.get_response = azx_get_response;
+#ifdef CONFIG_SND_HDA_POWER_SAVE
+	bus_temp.ops.pm_notify = azx_power_notify;
+#endif
 
 	err = snd_hda_bus_new(chip->card, &bus_temp, &chip->bus);
 	if (err < 0)
@@ -1128,9 +1164,11 @@ static int azx_pcm_open(struct snd_pcm_substream *substream)
 				   128);
 	snd_pcm_hw_constraint_step(runtime, 0, SNDRV_PCM_HW_PARAM_PERIOD_BYTES,
 				   128);
+	snd_hda_power_up(apcm->codec);
 	err = hinfo->ops.open(hinfo, apcm->codec, substream);
 	if (err < 0) {
 		azx_release_device(azx_dev);
+		snd_hda_power_down(apcm->codec);
 		mutex_unlock(&chip->open_mutex);
 		return err;
 	}
@@ -1159,6 +1197,7 @@ static int azx_pcm_close(struct snd_pcm_substream *substream)
 	spin_unlock_irqrestore(&chip->reg_lock, flags);
 	azx_release_device(azx_dev);
 	hinfo->ops.close(hinfo, apcm->codec, substream);
+	snd_hda_power_down(apcm->codec);
 	mutex_unlock(&chip->open_mutex);
 	return 0;
 }
@@ -1459,6 +1498,48 @@ static int azx_acquire_irq(struct azx *chip, int do_disconnect)
 }
 
 
+static void azx_stop_chip(struct azx *chip)
+{
+	if (chip->initialized)
+		return;
+
+	/* disable interrupts */
+	azx_int_disable(chip);
+	azx_int_clear(chip);
+
+	/* disable CORB/RIRB */
+	azx_free_cmd_io(chip);
+
+	/* disable position buffer */
+	azx_writel(chip, DPLBASE, 0);
+	azx_writel(chip, DPUBASE, 0);
+
+	chip->initialized = 0;
+}
+
+#ifdef CONFIG_SND_HDA_POWER_SAVE
+/* power-up/down the controller */
+static void azx_power_notify(struct hda_codec *codec)
+{
+	struct azx *chip = codec->bus->private_data;
+	struct hda_codec *c;
+	int power_on = 0;
+
+	list_for_each_entry(c, &codec->bus->codec_list, list) {
+		if (c->power_on) {
+			power_on = 1;
+			break;
+		}
+	}
+	if (power_on)
+		azx_init_chip(chip);
+#ifdef HDA_POWER_SAVE_RESET_CONTROLLER
+	else if (chip->running)
+		azx_stop_chip(chip);
+#endif
+}
+#endif /* CONFIG_SND_HDA_POWER_SAVE */
+
 #ifdef CONFIG_PM
 /*
  * power management
@@ -1473,7 +1554,7 @@ static int azx_suspend(struct pci_dev *pci, pm_message_t state)
 	for (i = 0; i < chip->pcm_devs; i++)
 		snd_pcm_suspend_all(chip->pcm[i]);
 	snd_hda_suspend(chip->bus, state);
-	azx_free_cmd_io(chip);
+	azx_stop_chip(chip);
 	if (chip->irq >= 0) {
 		synchronize_irq(chip->irq);
 		free_irq(chip->irq, chip);
@@ -1506,8 +1587,12 @@ static int azx_resume(struct pci_dev *pci)
 			chip->msi = 0;
 	if (azx_acquire_irq(chip, 1) < 0)
 		return -EIO;
+	azx_init_pci(chip);
+#ifndef CONFIG_SND_HDA_POWER_SAVE
+	/* the explicit resume is needed only when POWER_SAVE isn't set */
 	azx_init_chip(chip);
 	snd_hda_resume(chip->bus);
+#endif
 	snd_power_change_state(card, SNDRV_CTL_POWER_D0);
 	return 0;
 }
@@ -1521,20 +1606,9 @@ static int azx_free(struct azx *chip)
 {
 	if (chip->initialized) {
 		int i;
-
 		for (i = 0; i < chip->num_streams; i++)
 			azx_stream_stop(chip, &chip->azx_dev[i]);
-
-		/* disable interrupts */
-		azx_int_disable(chip);
-		azx_int_clear(chip);
-
-		/* disable CORB/RIRB */
-		azx_free_cmd_io(chip);
-
-		/* disable position buffer */
-		azx_writel(chip, DPLBASE, 0);
-		azx_writel(chip, DPUBASE, 0);
+		azx_stop_chip(chip);
 	}
 
 	if (chip->irq >= 0) {
@@ -1720,10 +1794,9 @@ static int __devinit azx_create(struct snd_card *card, struct pci_dev *pci,
 	azx_init_stream(chip);
 
 	/* initialize chip */
+	azx_init_pci(chip);
 	azx_init_chip(chip);
 
-	chip->initialized = 1;
-
 	/* codec detection */
 	if (!chip->codec_mask) {
 		snd_printk(KERN_ERR SFX "no codecs found!\n");
@@ -1750,6 +1823,19 @@ static int __devinit azx_create(struct snd_card *card, struct pci_dev *pci,
 	return err;
 }
 
+static void power_down_all_codecs(struct azx *chip)
+{
+#ifdef CONFIG_SND_HDA_POWER_SAVE
+	/* The codecs were powered up in snd_hda_codec_new().
+	 * Now all initialization done, so turn them down if possible
+	 */
+	struct hda_codec *codec;
+	list_for_each_entry(codec, &chip->bus->codec_list, list) {
+		snd_hda_power_down(codec);
+	}
+#endif
+}
+
 static int __devinit azx_probe(struct pci_dev *pci,
 			       const struct pci_device_id *pci_id)
 {
@@ -1800,6 +1886,8 @@ static int __devinit azx_probe(struct pci_dev *pci,
 	}
 
 	pci_set_drvdata(pci, card);
+	chip->running = 1;
+	power_down_all_codecs(chip);
 
 	return err;
 }