[PATCH 5/6] ALSA: hda: Skip controller resume if not needed

[Takashi Iwai <tiwai@suse.de>]

The HD-audio controller does system-suspend and resume operations by
directly calling its helpers __azx_runtime_suspend() and
__azx_runtime_resume().  However, in general, we don't have to resume
always the device fully at the system resume; typically, if a device
has been runtime-suspended, we can leave it to runtime resume.

Usually for achieving this, the driver would call
pm_runtime_force_suspend() and pm_runtime_force_resume() pairs in the
system suspend and resume ops.  Unfortunately, this doesn't work for
the resume path in our case.  For handling the jack detection at the
system resume, a child codec device may need the (literally) forcibly
resume even if it's been runtime-suspended, and for that, the
controller device must be also resumed even if it's been suspended.

This patch is an attempt to improve the situation.  It replaces the
direct __azx_runtime_suspend()/_resume() calls with with
pm_runtime_force_suspend() and pm_runtime_force_resume() with a slight
trick as we've done for the codec side.  More exactly:

- azx_has_pm_runtime() check is dropped from azx_runtime_suspend() and
  azx_runtime_resume(), so that it can be properly executed from the
  system-suspend/resume path

- The WAKEEN handling depends on the card's power state now; it's set
  and cleared only for the runtime-suspend

- azx_resume() checks whether any codec may need the forcible resume
  beforehand.  If the forcible resume is required, it does temporary
  PM refcount up/down for actually triggering the runtime resume.

- A new helper function, hda_codec_need_resume(), is introduced for
  checking whether the codec needs a forcible runtime-resume, and the
  existing code is rewritten with that.

BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=207043
Signed-off-by: Takashi Iwai <tiwai@suse.de>
---
 include/sound/hda_codec.h |  5 +++++
 sound/pci/hda/hda_codec.c |  2 +-
 sound/pci/hda/hda_intel.c | 38 +++++++++++++++++++++++++++-----------
 3 files changed, 33 insertions(+), 12 deletions(-)

diff --git a/include/sound/hda_codec.h b/include/sound/hda_codec.h
index 3ee8036f5436..225154a4f2ed 100644
--- a/include/sound/hda_codec.h
+++ b/include/sound/hda_codec.h
@@ -494,6 +494,11 @@ void snd_hda_update_power_acct(struct hda_codec *codec);
 static inline void snd_hda_set_power_save(struct hda_bus *bus, int delay) {}
 #endif
 
+static inline bool hda_codec_need_resume(struct hda_codec *codec)
+{
+	return !codec->relaxed_resume && codec->jacktbl.used;
+}
+
 #ifdef CONFIG_SND_HDA_PATCH_LOADER
 /*
  * patch firmware
diff --git a/sound/pci/hda/hda_codec.c b/sound/pci/hda/hda_codec.c
index a34a2c9f4bcf..86a632bf4d50 100644
--- a/sound/pci/hda/hda_codec.c
+++ b/sound/pci/hda/hda_codec.c
@@ -2951,7 +2951,7 @@ static int hda_codec_runtime_resume(struct device *dev)
 static int hda_codec_force_resume(struct device *dev)
 {
 	struct hda_codec *codec = dev_to_hda_codec(dev);
-	bool forced_resume = !codec->relaxed_resume && codec->jacktbl.used;
+	bool forced_resume = hda_codec_need_resume(codec);
 	int ret;
 
 	/* The get/put pair below enforces the runtime resume even if the
diff --git a/sound/pci/hda/hda_intel.c b/sound/pci/hda/hda_intel.c
index aa0be85614b6..02c6308502b1 100644
--- a/sound/pci/hda/hda_intel.c
+++ b/sound/pci/hda/hda_intel.c
@@ -1027,7 +1027,7 @@ static int azx_suspend(struct device *dev)
 	chip = card->private_data;
 	bus = azx_bus(chip);
 	snd_power_change_state(card, SNDRV_CTL_POWER_D3hot);
-	__azx_runtime_suspend(chip);
+	pm_runtime_force_suspend(dev);
 	if (bus->irq >= 0) {
 		free_irq(bus->irq, chip);
 		bus->irq = -1;
@@ -1044,7 +1044,9 @@ static int azx_suspend(struct device *dev)
 static int azx_resume(struct device *dev)
 {
 	struct snd_card *card = dev_get_drvdata(dev);
+	struct hda_codec *codec;
 	struct azx *chip;
+	bool forced_resume = false;
 
 	if (!azx_is_pm_ready(card))
 		return 0;
@@ -1055,7 +1057,20 @@ static int azx_resume(struct device *dev)
 			chip->msi = 0;
 	if (azx_acquire_irq(chip, 1) < 0)
 		return -EIO;
-	__azx_runtime_resume(chip, false);
+
+	/* check for the forced resume */
+	list_for_each_codec(codec, &chip->bus) {
+		if (hda_codec_need_resume(codec)) {
+			forced_resume = true;
+			break;
+		}
+	}
+
+	if (forced_resume)
+		pm_runtime_get_noresume(dev);
+	pm_runtime_force_resume(dev);
+	if (forced_resume)
+		pm_runtime_put(dev);
 	snd_power_change_state(card, SNDRV_CTL_POWER_D0);
 
 	trace_azx_resume(chip);
@@ -1102,12 +1117,12 @@ static int azx_runtime_suspend(struct device *dev)
 	if (!azx_is_pm_ready(card))
 		return 0;
 	chip = card->private_data;
-	if (!azx_has_pm_runtime(chip))
-		return 0;
 
 	/* enable controller wake up event */
-	azx_writew(chip, WAKEEN, azx_readw(chip, WAKEEN) |
-		  STATESTS_INT_MASK);
+	if (snd_power_get_state(card) == SNDRV_CTL_POWER_D0) {
+		azx_writew(chip, WAKEEN, azx_readw(chip, WAKEEN) |
+			   STATESTS_INT_MASK);
+	}
 
 	__azx_runtime_suspend(chip);
 	trace_azx_runtime_suspend(chip);
@@ -1118,17 +1133,18 @@ static int azx_runtime_resume(struct device *dev)
 {
 	struct snd_card *card = dev_get_drvdata(dev);
 	struct azx *chip;
+	bool from_rt = snd_power_get_state(card) == SNDRV_CTL_POWER_D0;
 
 	if (!azx_is_pm_ready(card))
 		return 0;
 	chip = card->private_data;
-	if (!azx_has_pm_runtime(chip))
-		return 0;
-	__azx_runtime_resume(chip, true);
+	__azx_runtime_resume(chip, from_rt);
 
 	/* disable controller Wake Up event*/
-	azx_writew(chip, WAKEEN, azx_readw(chip, WAKEEN) &
-			~STATESTS_INT_MASK);
+	if (from_rt) {
+		azx_writew(chip, WAKEEN, azx_readw(chip, WAKEEN) &
+			   ~STATESTS_INT_MASK);
+	}
 
 	trace_azx_runtime_resume(chip);
 	return 0;
-- 
2.16.4