[PATCH] ALSA: Realtek: Early Forbid of runtime PM

[PATCH] ALSA: Realtek: Early Forbid of runtime PM

[Harsha Priya]

For Realtek codecs, pm_runtime_forbid() is called in the probe function 
after the build_controls(). In a stress test, occasionally the runtime
PM calls are invoked before controls are built. This causes the codec to be
runtime suspended before probe completes. Because of this, not all
controls are enumerated correctly and audio does not work until
system is rebooted.

This patch calls pm_runtime_forbid() early to fix the issue.
Multiple stress tests of 2000+ cycles has been done to test the fix.

Signed-off-by: Harsha Priya <harshapriya.n@intel.com>
Signed-off-by: Emmanuel Jillela <emmanuel.jillela@intel.com>
Reviewed-by: Kailang Yang <kailang@realtek.com>

---
 sound/pci/hda/patch_realtek.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/sound/pci/hda/patch_realtek.c b/sound/pci/hda/patch_realtek.c
index 98789691a479..30ea07fd6735 100644
--- a/sound/pci/hda/patch_realtek.c
+++ b/sound/pci/hda/patch_realtek.c
@@ -8418,6 +8418,7 @@ static int patch_alc269(struct hda_codec *codec)
 {
 	struct alc_spec *spec;
 	int err;
+	struct device *dev = hda_codec_dev(codec);
 
 	err = alc_alloc_spec(codec, 0x0b);
 	if (err < 0)
@@ -8430,6 +8431,8 @@ static int patch_alc269(struct hda_codec *codec)
 #ifdef CONFIG_PM
 	codec->patch_ops.suspend = alc269_suspend;
 	codec->patch_ops.resume = alc269_resume;
+	pm_runtime_dont_use_autosuspend(dev);
+	pm_runtime_forbid(dev);
 #endif
 	spec->shutup = alc_default_shutup;
 	spec->init_hook = alc_default_init;
-- 
2.17.1

Re: [PATCH] ALSA: Realtek: Early Forbid of runtime PM

[Takashi Iwai]

On Thu, 27 Aug 2020 07:20:43 +0200,
Harsha Priya wrote:
> 
> For Realtek codecs, pm_runtime_forbid() is called in the probe function 
> after the build_controls(). In a stress test, occasionally the runtime
> PM calls are invoked before controls are built. This causes the codec to be
> runtime suspended before probe completes. Because of this, not all
> controls are enumerated correctly and audio does not work until
> system is rebooted.
> 
> This patch calls pm_runtime_forbid() early to fix the issue.
> Multiple stress tests of 2000+ cycles has been done to test the fix.
> 
> Signed-off-by: Harsha Priya <harshapriya.n@intel.com>
> Signed-off-by: Emmanuel Jillela <emmanuel.jillela@intel.com>
> Reviewed-by: Kailang Yang <kailang@realtek.com>

The behavior shouldn't be specific to that model, also not to codec
vendors, but it's rather a generic problem, so it's no right place to
correct, I suppose.

Can we simply call pm_runtime_forbid() at creating a codec object like
below?


thanks,

Takashi

--- a/sound/pci/hda/hda_codec.c
+++ b/sound/pci/hda/hda_codec.c
@@ -1000,6 +1000,9 @@ int snd_hda_codec_device_new(struct hda_bus *bus, struct snd_card *card,
 	if (err < 0)
 		goto error;
 
+	/* PM runtime needs to be enabled later after binding codec */
+	pm_runtime_forbid(&codec->core.dev);
+
 	return 0;
 
  error:

RE: [PATCH] ALSA: Realtek: Early Forbid of runtime PM

[N, Harshapriya]

 >
> > For Realtek codecs, pm_runtime_forbid() is called in the probe
> > function after the build_controls(). In a stress test, occasionally
> > the runtime PM calls are invoked before controls are built. This
> > causes the codec to be runtime suspended before probe completes.
> > Because of this, not all controls are enumerated correctly and audio
> > does not work until system is rebooted.
> >
> > This patch calls pm_runtime_forbid() early to fix the issue.
> > Multiple stress tests of 2000+ cycles has been done to test the fix.
> >
> > Signed-off-by: Harsha Priya <harshapriya.n@intel.com>
> > Signed-off-by: Emmanuel Jillela <emmanuel.jillela@intel.com>
> > Reviewed-by: Kailang Yang <kailang@realtek.com>
> 
> The behavior shouldn't be specific to that model, also not to codec vendors, but
> it's rather a generic problem, so it's no right place to correct, I suppose.
> 
> Can we simply call pm_runtime_forbid() at creating a codec object like below?
We tried this change and its working as expected. I believe this will address similar issues
across all codecs. Will send a patch with this fix.
> 
> 
> thanks,
> 
> Takashi
> 
> --- a/sound/pci/hda/hda_codec.c
> +++ b/sound/pci/hda/hda_codec.c
> @@ -1000,6 +1000,9 @@ int snd_hda_codec_device_new(struct hda_bus *bus,
> struct snd_card *card,
>  	if (err < 0)
>  		goto error;
> 
> +	/* PM runtime needs to be enabled later after binding codec */
> +	pm_runtime_forbid(&codec->core.dev);
> +
>  	return 0;
> 
>   error: