[PATCH] ASoC: dapm: don't call pm_runtime_* on card device

[Tzung-Bi Shih <tzungbi@google.com>]

runtime_usage of sound card has been observed to grow without bound.
For example:
$ cat /sys/devices/platform/sound/power/runtime_usage
46
$ sox -n -t s16 -r 48000 -c 2 - synth 1 sine 440 vol 0.1 | \
  aplay -q -D hw:0,0 -f S16_LE -r 48000 -c 2
$ cat /sys/devices/platform/sound/power/runtime_usage
52

Commit 4e872a46823c ("ASoC: dapm: Don't force card bias level to be
updated") stops to force update bias_level on card.  If card doesn't
provide set_bias_level callback, the snd_soc_dapm_set_bias_level()
is equivalent to NOP for card device.

As a result, dapm_pre_sequence_async() doesn't change the bias_level of
card device correctly.  Thus, pm_runtime_get_sync() would be called in
dapm_pre_sequence_async() without symmetric pm_runtime_put() in
dapm_post_sequence_async().

Don't call pm_runtime_* on card device.

Signed-off-by: Tzung-Bi Shih <tzungbi@google.com>
---
 sound/soc/soc-dapm.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Hi,
I'm not very sure if the patch makes sense.

I was considering:
(1) update the bias_level of card device correctly
(2) skip pm_runtime_* for card device

Per commit message on 4e872a46823c, I believe there is some context
I'm not aware of it.  Thus, the patch adopts (2).

diff --git a/sound/soc/soc-dapm.c b/sound/soc/soc-dapm.c
index 5076299abf37..3273161e2787 100644
--- a/sound/soc/soc-dapm.c
+++ b/sound/soc/soc-dapm.c
@@ -1798,7 +1798,7 @@ static void dapm_pre_sequence_async(void *data, async_cookie_t cookie)
 	/* If we're off and we're not supposed to go into STANDBY */
 	if (d->bias_level == SND_SOC_BIAS_OFF &&
 	    d->target_bias_level != SND_SOC_BIAS_OFF) {
-		if (d->dev)
+		if (d->dev && cookie)
 			pm_runtime_get_sync(d->dev);
 
 		ret = snd_soc_dapm_set_bias_level(d, SND_SOC_BIAS_STANDBY);
@@ -1845,7 +1845,7 @@ static void dapm_post_sequence_async(void *data, async_cookie_t cookie)
 			dev_err(d->dev, "ASoC: Failed to turn off bias: %d\n",
 				ret);
 
-		if (d->dev)
+		if (d->dev && cookie)
 			pm_runtime_put(d->dev);
 	}
 
-- 
2.28.0.rc0.142.g3c755180ce-goog