Re: [PATCH] ASoC: dapm: Fix the unpaired runtime_get/put cases

Re: [PATCH] ASoC: dapm: Fix the unpaired runtime_get/put cases

[Mark Brown]

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On Wed, Dec 19, 2012 at 06:36:37PM +0800, Chuansheng Liu wrote:

> But some devices has been set to STANDY bias directly during device probing,
> such as cs42l73_probe():
> cs42l73_set_bias_level(codec, SND_SOC_BIAS_STANDBY);

> Then it will cause runtime_get() not be called but laterly runtime_put() will
> be called. Also found some other uppaired cases.

This is just a bug in the driver, if it's idle_bias_off then it really
should be starting in _OFF or at the very least starting actually in
_STANDBY (including taking the runtime reference) rather than partially
in _STANDBY.

> So here add new flag get_runtime, and the logic will be:
> 1/ when device is from off to non-off bias, runtime_get() will be called if not yet;
> 2/ When device is off bias, runtime_put() will be called if runtime_get() has
>    been called;

This is really not a good idea at all, it's just adding new special
cases and making the code more obscure.

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[PATCH] ASoC: dapm: Fix the unpaired runtime_get/put cases

[Chuansheng Liu]

Commit f1aac484f7(Take a pm_runtime reference on DAPM devices that are enabled)
introduced runtime_get/put calling when devices are in off/non-off bias.

It is based on:
1/ device from off to non-off bias is called thru dapm_pre_sequence_async;
2/ device from non-off to off bias is called thru dapm_post_sequence_async;

There are the above conditions which then make sure runtime_get/put() are pairs.

But some devices has been set to STANDY bias directly during device probing,
such as cs42l73_probe():
cs42l73_set_bias_level(codec, SND_SOC_BIAS_STANDBY);

Then it will cause runtime_get() not be called but laterly runtime_put() will
be called. Also found some other uppaired cases.

So here add new flag get_runtime, and the logic will be:
1/ when device is from off to non-off bias, runtime_get() will be called if not yet;
2/ When device is off bias, runtime_put() will be called if runtime_get() has
   been called;

Signed-off-by: liu chuansheng <chuansheng.liu@intel.com>
---
 include/sound/soc-dapm.h |    1 +
 sound/soc/soc-dapm.c     |   18 ++++++++++++------
 2 files changed, 13 insertions(+), 6 deletions(-)

diff --git a/include/sound/soc-dapm.h b/include/sound/soc-dapm.h
index e1ef63d..e52fdcc 100644
--- a/include/sound/soc-dapm.h
+++ b/include/sound/soc-dapm.h
@@ -586,6 +586,7 @@ struct snd_soc_dapm_context {
 	struct list_head list;
 
 	int (*stream_event)(struct snd_soc_dapm_context *dapm, int event);
+	bool get_runtime;
 
 #ifdef CONFIG_DEBUG_FS
 	struct dentry *debugfs_dapm;
diff --git a/sound/soc/soc-dapm.c b/sound/soc/soc-dapm.c
index 1e36bc8..e6d030a 100644
--- a/sound/soc/soc-dapm.c
+++ b/sound/soc/soc-dapm.c
@@ -1460,12 +1460,15 @@ static void dapm_pre_sequence_async(void *data, async_cookie_t cookie)
 	struct snd_soc_dapm_context *d = data;
 	int ret;
 
+	if ((d->target_bias_level != SND_SOC_BIAS_OFF) &&
+		(d->dev) && !(d->get_runtime)) {
+		pm_runtime_get_sync(d->dev);
+		d->get_runtime = true;
+	}
+
 	/* If we're off and we're not supposed to be go into STANDBY */
 	if (d->bias_level == SND_SOC_BIAS_OFF &&
 	    d->target_bias_level != SND_SOC_BIAS_OFF) {
-		if (d->dev)
-			pm_runtime_get_sync(d->dev);
-
 		ret = snd_soc_dapm_set_bias_level(d, SND_SOC_BIAS_STANDBY);
 		if (ret != 0)
 			dev_err(d->dev,
@@ -1506,9 +1509,6 @@ static void dapm_post_sequence_async(void *data, async_cookie_t cookie)
 		if (ret != 0)
 			dev_err(d->dev, "ASoC: Failed to turn off bias: %d\n",
 				ret);
-
-		if (d->dev)
-			pm_runtime_put(d->dev);
 	}
 
 	/* If we just powered up then move to active bias */
@@ -1519,6 +1519,12 @@ static void dapm_post_sequence_async(void *data, async_cookie_t cookie)
 			dev_err(d->dev, "ASoC: Failed to apply active bias: %d\n",
 				ret);
 	}
+
+	if ((d->bias_level == SND_SOC_BIAS_OFF) &&
+		(d->dev) && (d->get_runtime)) {
+		pm_runtime_put(d->dev);
+		d->get_runtime = false;
+	}
 }
 
 static void dapm_widget_set_peer_power(struct snd_soc_dapm_widget *peer,
-- 
1.7.0.4

RE: [PATCH] ASoC: dapm: Fix the unpaired runtime_get/put cases

[Liu, Chuansheng]

> -----Original Message-----
> From: Mark Brown [mailto:broonie@opensource.wolfsonmicro.com]
> Sent: Wednesday, December 19, 2012 5:11 PM
> To: Liu, Chuansheng
> Cc: lrg@ti.com; perex@perex.cz; tiwai@suse.de; alsa-devel@alsa-project.org;
> linux-kernel@vger.kernel.org
> Subject: Re: [PATCH] ASoC: dapm: Fix the unpaired runtime_get/put cases
> 
> On Wed, Dec 19, 2012 at 06:36:37PM +0800, Chuansheng Liu wrote:
> 
> > But some devices has been set to STANDY bias directly during device probing,
> > such as cs42l73_probe():
> > cs42l73_set_bias_level(codec, SND_SOC_BIAS_STANDBY);
> 
> > Then it will cause runtime_get() not be called but laterly runtime_put() will
> > be called. Also found some other uppaired cases.
> 
> This is just a bug in the driver, if it's idle_bias_off then it really
> should be starting in _OFF or at the very least starting actually in
> _STANDBY (including taking the runtime reference) rather than partially
> in _STANDBY.
Thanks your pointing out. You are totally right.
Rechecked the related driver code, there is one place which starting from _STANDBY with idle_bias_off.
It should be the main reason of bringing unpaired issue.

Meanwhile, is it useful to add one warning there for that case?
After all, in probing, set the bias to _STANDBY even idle_bias_off == 1, and calling get_runtime_sync(), it
will let the code more obscure. So giving a warning there to indicate the driver:
it is not suggested that in probing, set the bias to _STANDBY even idle_bias_off == 1.

diff --git a/sound/soc/soc-core.c b/sound/soc/soc-core.c
index 9c768bc..d6adaec 100644
--- a/sound/soc/soc-core.c
+++ b/sound/soc/soc-core.c
@@ -1102,6 +1102,8 @@ static int soc_probe_codec(struct snd_soc_card *card,
 
        if (driver->probe) {
                ret = driver->probe(codec);
+               WARN_ON(codec->dapm.idle_bias_off &&
+                       codec->dapm.bias_level != SND_SOC_BIAS_OFF);
                if (ret < 0) {
                        dev_err(codec->dev,
                                "ASoC: failed to probe CODEC %d\n", ret);

Re: [PATCH] ASoC: dapm: Fix the unpaired runtime_get/put cases

[Mark Brown]

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On Thu, Dec 20, 2012 at 06:37:26AM +0000, Liu, Chuansheng wrote:

> Meanwhile, is it useful to add one warning there for that case?
> After all, in probing, set the bias to _STANDBY even idle_bias_off == 1, and calling get_runtime_sync(), it
> will let the code more obscure. So giving a warning there to indicate the driver:
> it is not suggested that in probing, set the bias to _STANDBY even idle_bias_off == 1.

Probably, send a patch please.  Like I say it is possible to start off
in _STANDBY providing the driver grabs the runtime PM reference too but
I can't think of any reason for doing that so the warning seems sensible.

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RE: [PATCH] ASoC: dapm: Fix the unpaired runtime_get/put cases

[Liu, Chuansheng]

> -----Original Message-----
> From: Mark Brown [mailto:broonie@opensource.wolfsonmicro.com]
> Sent: Thursday, December 20, 2012 9:51 PM
> To: Liu, Chuansheng
> Cc: lrg@ti.com; perex@perex.cz; tiwai@suse.de; alsa-devel@alsa-project.org;
> linux-kernel@vger.kernel.org
> Subject: Re: [PATCH] ASoC: dapm: Fix the unpaired runtime_get/put cases
> 
> On Thu, Dec 20, 2012 at 06:37:26AM +0000, Liu, Chuansheng wrote:
> 
> > Meanwhile, is it useful to add one warning there for that case?
> > After all, in probing, set the bias to _STANDBY even idle_bias_off == 1, and
> calling get_runtime_sync(), it
> > will let the code more obscure. So giving a warning there to indicate the
> driver:
> > it is not suggested that in probing, set the bias to _STANDBY even
> idle_bias_off == 1.
> 
> Probably, send a patch please.  Like I say it is possible to start off
> in _STANDBY providing the driver grabs the runtime PM reference too but
> I can't think of any reason for doing that so the warning seems sensible.
The patch https://lkml.org/lkml/2012/12/20/506 has been sent for giving warning
in that case. Thanks your reviewing.

[PATCH] ASoC: core: giving WARN when device starting from non-off bias with idle_bias_off

[Chuansheng Liu]

Just found some cases that some codec drivers set the bias to _STANDBY and
set idle_bias_off to 1 during probing.
It will cause unpaired runtime_get_sync/put() issue. Also as Mark suggested,
there is no reason to start from _STANDBY bias with idle_bias_off == 1.

So here giving one warning when detected (dapm.idle_bias_off == 1) and
(dapm.bias_level != SND_SOC_BIAS_OFF) just after driver->probe().

Signed-off-by: liu chuansheng <chuansheng.liu@intel.com>
---
 sound/soc/soc-core.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/sound/soc/soc-core.c b/sound/soc/soc-core.c
index 9c768bc..d7ec007 100644
--- a/sound/soc/soc-core.c
+++ b/sound/soc/soc-core.c
@@ -1107,6 +1107,10 @@ static int soc_probe_codec(struct snd_soc_card *card,
 				"ASoC: failed to probe CODEC %d\n", ret);
 			goto err_probe;
 		}
+		WARN(codec->dapm.idle_bias_off &&
+			codec->dapm.bias_level != SND_SOC_BIAS_OFF,
+			"codec %s can not start from non-off bias"
+			" with idle_bias_off==1\n", codec->name);
 	}
 
 	/* If the driver didn't set I/O up try regmap */
-- 
1.7.0.4

Re: [PATCH] ASoC: core: giving WARN when device starting from non-off bias with idle_bias_off

[Mark Brown]

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On Fri, Dec 21, 2012 at 06:17:12PM +0800, Chuansheng Liu wrote:
> 
> Just found some cases that some codec drivers set the bias to _STANDBY and
> set idle_bias_off to 1 during probing.
> It will cause unpaired runtime_get_sync/put() issue. Also as Mark suggested,
> there is no reason to start from _STANDBY bias with idle_bias_off == 1.

Applied, thanks.

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