[PATCH 0/3] More robust i915 / audio binding

[PATCH 0/3] More robust i915 / audio binding

[Takashi Iwai]

Hi,

here is a patchset to make the i915 / audio binding more robustly.
It's based on Imre's work to implement the stub component ops for
notifying the i915 disablement.


Takashi

===

Imre Deak (1):
  drm/i915/hda: Add audio component stub

Takashi Iwai (2):
  ALSA: hda - Immediately fail if the i915 audio component is disabled
  ALSA: hda - Support deferred i915 audio component binding

 drivers/gpu/drm/i915/i915_drv.c    | 34 +++++++++++++--------
 drivers/gpu/drm/i915/intel_audio.c | 61 ++++++++++++++++++++++++++++++++++++++
 drivers/gpu/drm/i915/intel_drv.h   |  2 ++
 include/drm/i915_component.h       |  5 ++++
 sound/hda/hdac_i915.c              | 28 ++++++++++++-----
 5 files changed, 110 insertions(+), 20 deletions(-)

-- 
2.8.1

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[PATCH 1/3] drm/i915/hda: Add audio component stub

[Takashi Iwai]

From: Imre Deak <imre.deak@intel.com>

User may pass nomodeset or i915.modeset=0 option to disable i915 KMS
explicitly.  Although this itself works fine, it breaks the weak
dependency the HD-audio driver requires, and it's the reason the
delayed component binding isn't implemented in HD-audio.  Since i915
doesn't notify its disablement, HD-audio would be blocked
unnecessarily endlessly, waiting for the bind with i915.

This patch introduces a stub audio component binding when i915 driver
is loaded with KMS off like the boot options above.  Then i915 driver
still registers the slave component but with the new "disabled" ops
flag, so that the master component (HD-audio) can know clearly the
slave state.

Signed-off-by: Imre Deak <imre.deak@intel.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
---
 drivers/gpu/drm/i915/i915_drv.c    | 34 +++++++++++++--------
 drivers/gpu/drm/i915/intel_audio.c | 61 ++++++++++++++++++++++++++++++++++++++
 drivers/gpu/drm/i915/intel_drv.h   |  2 ++
 include/drm/i915_component.h       |  5 ++++
 4 files changed, 90 insertions(+), 12 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index 20e82008b8b6..21c6bac5468e 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -950,6 +950,19 @@ static int i915_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 	struct intel_device_info *intel_info =
 		(struct intel_device_info *) ent->driver_data;
 
+	if (!(driver.driver_features & DRIVER_MODESET)) {
+		/*
+		 * Notify the HDA driver so that it doesn't block waiting for
+		 * i915 to become ready.
+		 */
+		i915_audio_component_stub_init(&pdev->dev);
+
+		/* Silently fail loading to not upset userspace. */
+		DRM_DEBUG_DRIVER("KMS and UMS disabled.\n");
+
+		return 0;
+	}
+
 	if (IS_PRELIMINARY_HW(intel_info) && !i915.preliminary_hw_support) {
 		DRM_INFO("This hardware requires preliminary hardware support.\n"
 			 "See CONFIG_DRM_I915_PRELIMINARY_HW_SUPPORT, and/or modparam preliminary_hw_support\n");
@@ -979,8 +992,14 @@ static int i915_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 static void
 i915_pci_remove(struct pci_dev *pdev)
 {
-	struct drm_device *dev = pci_get_drvdata(pdev);
+	struct drm_device *dev;
 
+	if (!(driver.driver_features & DRIVER_MODESET)) {
+		i915_audio_component_stub_cleanup(&pdev->dev);
+		return;
+	}
+
+	dev = pci_get_drvdata(pdev);
 	drm_put_dev(dev);
 }
 
@@ -1747,24 +1766,15 @@ static int __init i915_init(void)
 		driver.driver_features &= ~DRIVER_MODESET;
 #endif
 
-	if (!(driver.driver_features & DRIVER_MODESET)) {
-		/* Silently fail loading to not upset userspace. */
-		DRM_DEBUG_DRIVER("KMS and UMS disabled.\n");
-		return 0;
-	}
-
 	if (i915.nuclear_pageflip)
 		driver.driver_features |= DRIVER_ATOMIC;
 
-	return drm_pci_init(&driver, &i915_pci_driver);
+	return pci_register_driver(&i915_pci_driver);
 }
 
 static void __exit i915_exit(void)
 {
-	if (!(driver.driver_features & DRIVER_MODESET))
-		return; /* Never loaded a driver. */
-
-	drm_pci_exit(&driver, &i915_pci_driver);
+	pci_unregister_driver(&i915_pci_driver);
 }
 
 module_init(i915_init);
diff --git a/drivers/gpu/drm/i915/intel_audio.c b/drivers/gpu/drm/i915/intel_audio.c
index 30f921421b0c..bd9e9760903a 100644
--- a/drivers/gpu/drm/i915/intel_audio.c
+++ b/drivers/gpu/drm/i915/intel_audio.c
@@ -835,3 +835,64 @@ void i915_audio_component_cleanup(struct drm_i915_private *dev_priv)
 	component_del(dev_priv->dev->dev, &i915_audio_component_bind_ops);
 	dev_priv->audio_component_registered = false;
 }
+
+static const struct i915_audio_component_ops i915_audio_component_stub_ops = {
+	.owner		= THIS_MODULE,
+	.disabled	= true,
+};
+
+static int i915_audio_component_stub_bind(struct device *i915_stub_dev,
+					  struct device *hda_dev, void *data)
+{
+	struct i915_audio_component *acomp = data;
+
+	if (WARN_ON(acomp->ops || acomp->dev))
+		return -EEXIST;
+
+	acomp->ops = &i915_audio_component_stub_ops;
+	acomp->dev = i915_stub_dev;
+
+	return 0;
+}
+
+static void i915_audio_component_stub_unbind(struct device *i915_stub_dev,
+					     struct device *hda_dev, void *data)
+{
+	struct i915_audio_component *acomp = data;
+
+	acomp->ops = NULL;
+	acomp->dev = NULL;
+}
+
+static const struct component_ops i915_audio_component_stub_bind_ops = {
+	.bind	= i915_audio_component_stub_bind,
+	.unbind	= i915_audio_component_stub_unbind,
+};
+
+static const struct file_operations component_stub_dev_ops = {
+	.owner = THIS_MODULE,
+};
+
+static bool i915_audio_component_stub_registered;
+
+void i915_audio_component_stub_init(struct device *dev)
+{
+	int ret;
+
+	ret = component_add(dev, &i915_audio_component_stub_bind_ops);
+	if (ret < 0) {
+		DRM_ERROR("failed to add audio stub component (%d)\n", ret);
+		return;
+	}
+
+	i915_audio_component_stub_registered = true;
+}
+
+void i915_audio_component_stub_cleanup(struct device *dev)
+{
+	if (!i915_audio_component_stub_registered)
+		return;
+
+	component_del(dev, &i915_audio_component_stub_bind_ops);
+	i915_audio_component_stub_registered = false;
+}
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 4c027d69fac9..e1d9c33b113e 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -1056,6 +1056,8 @@ void intel_audio_codec_enable(struct intel_encoder *encoder);
 void intel_audio_codec_disable(struct intel_encoder *encoder);
 void i915_audio_component_init(struct drm_i915_private *dev_priv);
 void i915_audio_component_cleanup(struct drm_i915_private *dev_priv);
+void i915_audio_component_stub_init(struct device *dev);
+void i915_audio_component_stub_cleanup(struct device *dev);
 
 /* intel_display.c */
 extern const struct drm_plane_funcs intel_plane_funcs;
diff --git a/include/drm/i915_component.h b/include/drm/i915_component.h
index b46fa0ef3005..33da85aa70c3 100644
--- a/include/drm/i915_component.h
+++ b/include/drm/i915_component.h
@@ -39,6 +39,11 @@ struct i915_audio_component_ops {
 	 */
 	struct module *owner;
 	/**
+	 * @disabled: i915 driver loaded with modeset=0, the services provided
+	 * via the audio component interface are not available.
+	 */
+	bool disabled;
+	/**
 	 * @get_power: get the POWER_DOMAIN_AUDIO power well
 	 *
 	 * Request the power well to be turned on.
-- 
2.8.1

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[PATCH 2/3] ALSA: hda - Immediately fail if the i915 audio component is disabled

[Takashi Iwai]

Since i915 notifies its disabled state via the stub component binding,
we can bail out immediately once when the disabled flag is detected.

Based on the original patch by Imre Deak <imre.deak@intel.com>

Signed-off-by: Takashi Iwai <tiwai@suse.de>
---
 sound/hda/hdac_i915.c | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/sound/hda/hdac_i915.c b/sound/hda/hdac_i915.c
index 6800e0c5a38f..812777f9af1f 100644
--- a/sound/hda/hdac_i915.c
+++ b/sound/hda/hdac_i915.c
@@ -223,8 +223,18 @@ static int hdac_component_master_bind(struct device *dev)
 	if (ret < 0)
 		return ret;
 
-	if (WARN_ON(!(acomp->dev && acomp->ops && acomp->ops->get_power &&
-		      acomp->ops->put_power && acomp->ops->get_cdclk_freq))) {
+	if (WARN_ON(!(acomp->dev && acomp->ops))) {
+		ret = -EINVAL;
+		goto out_unbind;
+	}
+
+	if (acomp->ops->disabled) {
+		ret = -ENODEV;
+		goto out_unbind;
+	}
+
+	if (WARN_ON(!(acomp->ops->get_power && acomp->ops->put_power &&
+		      acomp->ops->get_cdclk_freq))) {
 		ret = -EINVAL;
 		goto out_unbind;
 	}
@@ -342,7 +352,7 @@ int snd_hdac_i915_init(struct hdac_bus *bus)
 	 */
 	request_module("i915");
 
-	if (!acomp->ops) {
+	if (!acomp->ops || acomp->ops->disabled) {
 		ret = -ENODEV;
 		goto out_master_del;
 	}
-- 
2.8.1

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[PATCH 3/3] ALSA: hda - Support deferred i915 audio component binding

[Takashi Iwai]

Since we have the reliable way to detect the availability of i915
audio component, the HD-audio driver may wait for the binding safely.

This patch puts a simple completion call in the binding callback and
let snd_hdac_i915_init() waiting until the i915 component gets bound
or it notifies.

The wait for binding has a timeout of 60 seconds, in case where the
i915 module isn't present on the media by some reason.  Such a
situation is rather the system error, but it's still safe to get a
timeout and indicate user about that.

The explicit call of request_module() is still kept in this patch in
order to avoid regression even for a system without the implicit
driver loading.  But now it's called in the condition only when no ops
is found, so it's slightly optimized.

The pin-down of i915 module is still kept, too, as the dynamic
unbinding is still problematic.  It may be racy and lead to the
refcount unbalance.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
---
 sound/hda/hdac_i915.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/sound/hda/hdac_i915.c b/sound/hda/hdac_i915.c
index 812777f9af1f..6455d239a928 100644
--- a/sound/hda/hdac_i915.c
+++ b/sound/hda/hdac_i915.c
@@ -22,6 +22,7 @@
 #include <sound/hda_i915.h>
 
 static struct i915_audio_component *hdac_acomp;
+static DECLARE_COMPLETION(bind_comp);
 
 /**
  * snd_hdac_set_codec_wakeup - Enable / disable HDMI/DP codec wakeup
@@ -248,10 +249,12 @@ static int hdac_component_master_bind(struct device *dev)
 		goto out_unbind;
 	}
 
+	complete_all(&bind_comp);
 	return 0;
 
 out_unbind:
 	component_unbind_all(dev, acomp);
+	complete_all(&bind_comp);
 
 	return ret;
 }
@@ -339,6 +342,7 @@ int snd_hdac_i915_init(struct hdac_bus *bus)
 		return -ENOMEM;
 	bus->audio_component = acomp;
 	hdac_acomp = acomp;
+	init_completion(&bind_comp);
 
 	component_match_add(dev, &match, hdac_component_master_match, bus);
 	ret = component_master_add_with_match(dev, &hdac_component_master_ops,
@@ -346,12 +350,10 @@ int snd_hdac_i915_init(struct hdac_bus *bus)
 	if (ret < 0)
 		goto out_err;
 
-	/*
-	 * Atm, we don't support deferring the component binding, so make sure
-	 * i915 is loaded and that the binding successfully completes.
-	 */
-	request_module("i915");
+	if (!acomp->ops)
+		request_module("i915");
 
+	wait_for_completion_timeout(&bind_comp, msecs_to_jiffies(60 * 1000));
 	if (!acomp->ops || acomp->ops->disabled) {
 		ret = -ENODEV;
 		goto out_master_del;
-- 
2.8.1

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Re: [PATCH 1/3] drm/i915/hda: Add audio component stub

[Ville Syrjälä]

On Thu, Apr 07, 2016 at 12:57:22PM +0200, Takashi Iwai wrote:
> From: Imre Deak <imre.deak@intel.com>
> 
> User may pass nomodeset or i915.modeset=0 option to disable i915 KMS
> explicitly.  Although this itself works fine, it breaks the weak
> dependency the HD-audio driver requires, and it's the reason the
> delayed component binding isn't implemented in HD-audio.  Since i915
> doesn't notify its disablement, HD-audio would be blocked
> unnecessarily endlessly, waiting for the bind with i915.
> 
> This patch introduces a stub audio component binding when i915 driver
> is loaded with KMS off like the boot options above.  Then i915 driver
> still registers the slave component but with the new "disabled" ops
> flag, so that the master component (HD-audio) can know clearly the
> slave state.
> 
> Signed-off-by: Imre Deak <imre.deak@intel.com>
> Signed-off-by: Takashi Iwai <tiwai@suse.de>
> ---
>  drivers/gpu/drm/i915/i915_drv.c    | 34 +++++++++++++--------
>  drivers/gpu/drm/i915/intel_audio.c | 61 ++++++++++++++++++++++++++++++++++++++
>  drivers/gpu/drm/i915/intel_drv.h   |  2 ++
>  include/drm/i915_component.h       |  5 ++++
>  4 files changed, 90 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
> index 20e82008b8b6..21c6bac5468e 100644
> --- a/drivers/gpu/drm/i915/i915_drv.c
> +++ b/drivers/gpu/drm/i915/i915_drv.c
> @@ -950,6 +950,19 @@ static int i915_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
>  	struct intel_device_info *intel_info =
>  		(struct intel_device_info *) ent->driver_data;
>  
> +	if (!(driver.driver_features & DRIVER_MODESET)) {
> +		/*
> +		 * Notify the HDA driver so that it doesn't block waiting for
> +		 * i915 to become ready.
> +		 */
> +		i915_audio_component_stub_init(&pdev->dev);
> +
> +		/* Silently fail loading to not upset userspace. */
> +		DRM_DEBUG_DRIVER("KMS and UMS disabled.\n");
> +
> +		return 0;
> +	}
> +

Moving this here means we're actually going to bind to the device even
w/o DRIVER_MODESET. Hopefully the fact that we don't register with any
subsystems would make that OK. But since we need the actual device for
the component stuff, I guess this is the only way.

>  	if (IS_PRELIMINARY_HW(intel_info) && !i915.preliminary_hw_support) {
>  		DRM_INFO("This hardware requires preliminary hardware support.\n"
>  			 "See CONFIG_DRM_I915_PRELIMINARY_HW_SUPPORT, and/or modparam preliminary_hw_support\n");
> @@ -979,8 +992,14 @@ static int i915_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
>  static void
>  i915_pci_remove(struct pci_dev *pdev)
>  {
> -	struct drm_device *dev = pci_get_drvdata(pdev);
> +	struct drm_device *dev;
>  
> +	if (!(driver.driver_features & DRIVER_MODESET)) {
> +		i915_audio_component_stub_cleanup(&pdev->dev);
> +		return;
> +	}
> +
> +	dev = pci_get_drvdata(pdev);
>  	drm_put_dev(dev);
>  }
>  
> @@ -1747,24 +1766,15 @@ static int __init i915_init(void)
>  		driver.driver_features &= ~DRIVER_MODESET;
>  #endif
>  
> -	if (!(driver.driver_features & DRIVER_MODESET)) {
> -		/* Silently fail loading to not upset userspace. */
> -		DRM_DEBUG_DRIVER("KMS and UMS disabled.\n");
> -		return 0;
> -	}
> -
>  	if (i915.nuclear_pageflip)
>  		driver.driver_features |= DRIVER_ATOMIC;
>  
> -	return drm_pci_init(&driver, &i915_pci_driver);
> +	return pci_register_driver(&i915_pci_driver);
>  }
>  
>  static void __exit i915_exit(void)
>  {
> -	if (!(driver.driver_features & DRIVER_MODESET))
> -		return; /* Never loaded a driver. */
> -
> -	drm_pci_exit(&driver, &i915_pci_driver);
> +	pci_unregister_driver(&i915_pci_driver);
>  }
>  
>  module_init(i915_init);
> diff --git a/drivers/gpu/drm/i915/intel_audio.c b/drivers/gpu/drm/i915/intel_audio.c
> index 30f921421b0c..bd9e9760903a 100644
> --- a/drivers/gpu/drm/i915/intel_audio.c
> +++ b/drivers/gpu/drm/i915/intel_audio.c
> @@ -835,3 +835,64 @@ void i915_audio_component_cleanup(struct drm_i915_private *dev_priv)
>  	component_del(dev_priv->dev->dev, &i915_audio_component_bind_ops);
>  	dev_priv->audio_component_registered = false;
>  }
> +
> +static const struct i915_audio_component_ops i915_audio_component_stub_ops = {
> +	.owner		= THIS_MODULE,
> +	.disabled	= true,
> +};
> +
> +static int i915_audio_component_stub_bind(struct device *i915_stub_dev,
> +					  struct device *hda_dev, void *data)
> +{
> +	struct i915_audio_component *acomp = data;
> +
> +	if (WARN_ON(acomp->ops || acomp->dev))
> +		return -EEXIST;
> +
> +	acomp->ops = &i915_audio_component_stub_ops;
> +	acomp->dev = i915_stub_dev;
> +
> +	return 0;
> +}
> +
> +static void i915_audio_component_stub_unbind(struct device *i915_stub_dev,
> +					     struct device *hda_dev, void *data)
> +{
> +	struct i915_audio_component *acomp = data;
> +
> +	acomp->ops = NULL;
> +	acomp->dev = NULL;
> +}
> +
> +static const struct component_ops i915_audio_component_stub_bind_ops = {
> +	.bind	= i915_audio_component_stub_bind,
> +	.unbind	= i915_audio_component_stub_unbind,
> +};
> +
> +static const struct file_operations component_stub_dev_ops = {
> +	.owner = THIS_MODULE,
> +};
> +
> +static bool i915_audio_component_stub_registered;
> +
> +void i915_audio_component_stub_init(struct device *dev)
> +{
> +	int ret;
> +
> +	ret = component_add(dev, &i915_audio_component_stub_bind_ops);
> +	if (ret < 0) {
> +		DRM_ERROR("failed to add audio stub component (%d)\n", ret);
> +		return;
> +	}
> +
> +	i915_audio_component_stub_registered = true;

Maybe just fail the probe on error and avoid the flag?

> +}
> +
> +void i915_audio_component_stub_cleanup(struct device *dev)
> +{
> +	if (!i915_audio_component_stub_registered)
> +		return;
> +
> +	component_del(dev, &i915_audio_component_stub_bind_ops);
> +	i915_audio_component_stub_registered = false;
> +}
> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> index 4c027d69fac9..e1d9c33b113e 100644
> --- a/drivers/gpu/drm/i915/intel_drv.h
> +++ b/drivers/gpu/drm/i915/intel_drv.h
> @@ -1056,6 +1056,8 @@ void intel_audio_codec_enable(struct intel_encoder *encoder);
>  void intel_audio_codec_disable(struct intel_encoder *encoder);
>  void i915_audio_component_init(struct drm_i915_private *dev_priv);
>  void i915_audio_component_cleanup(struct drm_i915_private *dev_priv);
> +void i915_audio_component_stub_init(struct device *dev);
> +void i915_audio_component_stub_cleanup(struct device *dev);
>  
>  /* intel_display.c */
>  extern const struct drm_plane_funcs intel_plane_funcs;
> diff --git a/include/drm/i915_component.h b/include/drm/i915_component.h
> index b46fa0ef3005..33da85aa70c3 100644
> --- a/include/drm/i915_component.h
> +++ b/include/drm/i915_component.h
> @@ -39,6 +39,11 @@ struct i915_audio_component_ops {
>  	 */
>  	struct module *owner;
>  	/**
> +	 * @disabled: i915 driver loaded with modeset=0, the services provided
> +	 * via the audio component interface are not available.
> +	 */
> +	bool disabled;
> +	/**
>  	 * @get_power: get the POWER_DOMAIN_AUDIO power well
>  	 *
>  	 * Request the power well to be turned on.
> -- 
> 2.8.1
> 
> _______________________________________________
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> https://lists.freedesktop.org/mailman/listinfo/intel-gfx

-- 
Ville Syrjälä
Intel OTC
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Re: [PATCH 1/3] drm/i915/hda: Add audio component stub

[Imre Deak]

On to, 2016-04-07 at 14:55 +0300, Ville Syrjälä wrote:
> On Thu, Apr 07, 2016 at 12:57:22PM +0200, Takashi Iwai wrote:
> > From: Imre Deak <imre.deak@intel.com>
> > 
> > User may pass nomodeset or i915.modeset=0 option to disable i915
> > KMS
> > explicitly.  Although this itself works fine, it breaks the weak
> > dependency the HD-audio driver requires, and it's the reason the
> > delayed component binding isn't implemented in HD-audio.  Since
> > i915
> > doesn't notify its disablement, HD-audio would be blocked
> > unnecessarily endlessly, waiting for the bind with i915.
> > 
> > This patch introduces a stub audio component binding when i915
> > driver
> > is loaded with KMS off like the boot options above.  Then i915
> > driver
> > still registers the slave component but with the new "disabled" ops
> > flag, so that the master component (HD-audio) can know clearly the
> > slave state.
> > 
> > Signed-off-by: Imre Deak <imre.deak@intel.com>
> > Signed-off-by: Takashi Iwai <tiwai@suse.de>
> > ---
> >  drivers/gpu/drm/i915/i915_drv.c    | 34 +++++++++++++--------
> >  drivers/gpu/drm/i915/intel_audio.c | 61
> > ++++++++++++++++++++++++++++++++++++++
> >  drivers/gpu/drm/i915/intel_drv.h   |  2 ++
> >  include/drm/i915_component.h       |  5 ++++
> >  4 files changed, 90 insertions(+), 12 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/i915_drv.c
> > b/drivers/gpu/drm/i915/i915_drv.c
> > index 20e82008b8b6..21c6bac5468e 100644
> > --- a/drivers/gpu/drm/i915/i915_drv.c
> > +++ b/drivers/gpu/drm/i915/i915_drv.c
> > @@ -950,6 +950,19 @@ static int i915_pci_probe(struct pci_dev
> > *pdev, const struct pci_device_id *ent)
> >  	struct intel_device_info *intel_info =
> >  		(struct intel_device_info *) ent->driver_data;
> >  
> > +	if (!(driver.driver_features & DRIVER_MODESET)) {
> > +		/*
> > +		 * Notify the HDA driver so that it doesn't block
> > waiting for
> > +		 * i915 to become ready.
> > +		 */
> > +		i915_audio_component_stub_init(&pdev->dev);
> > +
> > +		/* Silently fail loading to not upset userspace.
> > */
> > +		DRM_DEBUG_DRIVER("KMS and UMS disabled.\n");
> > +
> > +		return 0;
> > +	}
> > +
> 
> Moving this here means we're actually going to bind to the device
> even
> w/o DRIVER_MODESET. Hopefully the fact that we don't register with
> any
> subsystems would make that OK. But since we need the actual device
> for
> the component stuff, I guess this is the only way.

Yes, the need for the device was the reason I moved this here. An
alternative would be to add a miscdevice. I wanted to keep things
simple and didn't see any problem of keeping the device bound, so chose
this way.

One other thing I was thinking about is to also bind the stub component
if the real probing failed to make things more consistent and avoid the
longish timeout on the HDA side. This would also get messier with the
miscdevice approach, since the probe error is not propagated to the
caller of pci_register_driver(). If people don't see a problem with
this I could add this in the next version.

> >  	if (IS_PRELIMINARY_HW(intel_info) &&
> > !i915.preliminary_hw_support) {
> >  		DRM_INFO("This hardware requires preliminary
> > hardware support.\n"
> >  			 "See
> > CONFIG_DRM_I915_PRELIMINARY_HW_SUPPORT, and/or modparam
> > preliminary_hw_support\n");
> > @@ -979,8 +992,14 @@ static int i915_pci_probe(struct pci_dev
> > *pdev, const struct pci_device_id *ent)
> >  static void
> >  i915_pci_remove(struct pci_dev *pdev)
> >  {
> > -	struct drm_device *dev = pci_get_drvdata(pdev);
> > +	struct drm_device *dev;
> >  
> > +	if (!(driver.driver_features & DRIVER_MODESET)) {
> > +		i915_audio_component_stub_cleanup(&pdev->dev);
> > +		return;
> > +	}
> > +
> > +	dev = pci_get_drvdata(pdev);
> >  	drm_put_dev(dev);
> >  }
> >  
> > @@ -1747,24 +1766,15 @@ static int __init i915_init(void)
> >  		driver.driver_features &= ~DRIVER_MODESET;
> >  #endif
> >  
> > -	if (!(driver.driver_features & DRIVER_MODESET)) {
> > -		/* Silently fail loading to not upset userspace.
> > */
> > -		DRM_DEBUG_DRIVER("KMS and UMS disabled.\n");
> > -		return 0;
> > -	}
> > -
> >  	if (i915.nuclear_pageflip)
> >  		driver.driver_features |= DRIVER_ATOMIC;
> >  
> > -	return drm_pci_init(&driver, &i915_pci_driver);
> > +	return pci_register_driver(&i915_pci_driver);
> >  }
> >  
> >  static void __exit i915_exit(void)
> >  {
> > -	if (!(driver.driver_features & DRIVER_MODESET))
> > -		return; /* Never loaded a driver. */
> > -
> > -	drm_pci_exit(&driver, &i915_pci_driver);
> > +	pci_unregister_driver(&i915_pci_driver);
> >  }
> >  
> >  module_init(i915_init);
> > diff --git a/drivers/gpu/drm/i915/intel_audio.c
> > b/drivers/gpu/drm/i915/intel_audio.c
> > index 30f921421b0c..bd9e9760903a 100644
> > --- a/drivers/gpu/drm/i915/intel_audio.c
> > +++ b/drivers/gpu/drm/i915/intel_audio.c
> > @@ -835,3 +835,64 @@ void i915_audio_component_cleanup(struct
> > drm_i915_private *dev_priv)
> >  	component_del(dev_priv->dev->dev,
> > &i915_audio_component_bind_ops);
> >  	dev_priv->audio_component_registered = false;
> >  }
> > +
> > +static const struct i915_audio_component_ops
> > i915_audio_component_stub_ops = {
> > +	.owner		= THIS_MODULE,
> > +	.disabled	= true,
> > +};
> > +
> > +static int i915_audio_component_stub_bind(struct device
> > *i915_stub_dev,
> > +					  struct device *hda_dev,
> > void *data)
> > +{
> > +	struct i915_audio_component *acomp = data;
> > +
> > +	if (WARN_ON(acomp->ops || acomp->dev))
> > +		return -EEXIST;
> > +
> > +	acomp->ops = &i915_audio_component_stub_ops;
> > +	acomp->dev = i915_stub_dev;
> > +
> > +	return 0;
> > +}
> > +
> > +static void i915_audio_component_stub_unbind(struct device
> > *i915_stub_dev,
> > +					     struct device
> > *hda_dev, void *data)
> > +{
> > +	struct i915_audio_component *acomp = data;
> > +
> > +	acomp->ops = NULL;
> > +	acomp->dev = NULL;
> > +}
> > +
> > +static const struct component_ops
> > i915_audio_component_stub_bind_ops = {
> > +	.bind	= i915_audio_component_stub_bind,
> > +	.unbind	= i915_audio_component_stub_unbind,
> > +};
> > +
> > +static const struct file_operations component_stub_dev_ops = {
> > +	.owner = THIS_MODULE,
> > +};
> > +
> > +static bool i915_audio_component_stub_registered;
> > +
> > +void i915_audio_component_stub_init(struct device *dev)
> > +{
> > +	int ret;
> > +
> > +	ret = component_add(dev,
> > &i915_audio_component_stub_bind_ops);
> > +	if (ret < 0) {
> > +		DRM_ERROR("failed to add audio stub component
> > (%d)\n", ret);
> > +		return;
> > +	}
> > +
> > +	i915_audio_component_stub_registered = true;
> 
> Maybe just fail the probe on error and avoid the flag?

Makes sense, will change that.

> > +}
> > +
> > +void i915_audio_component_stub_cleanup(struct device *dev)
> > +{
> > +	if (!i915_audio_component_stub_registered)
> > +		return;
> > +
> > +	component_del(dev, &i915_audio_component_stub_bind_ops);
> > +	i915_audio_component_stub_registered = false;
> > +}
> > diff --git a/drivers/gpu/drm/i915/intel_drv.h
> > b/drivers/gpu/drm/i915/intel_drv.h
> > index 4c027d69fac9..e1d9c33b113e 100644
> > --- a/drivers/gpu/drm/i915/intel_drv.h
> > +++ b/drivers/gpu/drm/i915/intel_drv.h
> > @@ -1056,6 +1056,8 @@ void intel_audio_codec_enable(struct
> > intel_encoder *encoder);
> >  void intel_audio_codec_disable(struct intel_encoder *encoder);
> >  void i915_audio_component_init(struct drm_i915_private *dev_priv);
> >  void i915_audio_component_cleanup(struct drm_i915_private
> > *dev_priv);
> > +void i915_audio_component_stub_init(struct device *dev);
> > +void i915_audio_component_stub_cleanup(struct device *dev);
> >  
> >  /* intel_display.c */
> >  extern const struct drm_plane_funcs intel_plane_funcs;
> > diff --git a/include/drm/i915_component.h
> > b/include/drm/i915_component.h
> > index b46fa0ef3005..33da85aa70c3 100644
> > --- a/include/drm/i915_component.h
> > +++ b/include/drm/i915_component.h
> > @@ -39,6 +39,11 @@ struct i915_audio_component_ops {
> >  	 */
> >  	struct module *owner;
> >  	/**
> > +	 * @disabled: i915 driver loaded with modeset=0, the
> > services provided
> > +	 * via the audio component interface are not available.
> > +	 */
> > +	bool disabled;
> > +	/**
> >  	 * @get_power: get the POWER_DOMAIN_AUDIO power well
> >  	 *
> >  	 * Request the power well to be turned on.
> > -- 
> > 2.8.1
> > 
> > _______________________________________________
> > Intel-gfx mailing list
> > Intel-gfx@lists.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/intel-gfx
> 
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Re: [PATCH 1/3] drm/i915/hda: Add audio component stub

[Takashi Iwai]

On Thu, 07 Apr 2016 14:30:45 +0200,
Imre Deak wrote:
> 
> On to, 2016-04-07 at 14:55 +0300, Ville Syrjälä wrote:
> > On Thu, Apr 07, 2016 at 12:57:22PM +0200, Takashi Iwai wrote:
> > > From: Imre Deak <imre.deak@intel.com>
> > > 
> > > User may pass nomodeset or i915.modeset=0 option to disable i915
> > > KMS
> > > explicitly.  Although this itself works fine, it breaks the weak
> > > dependency the HD-audio driver requires, and it's the reason the
> > > delayed component binding isn't implemented in HD-audio.  Since
> > > i915
> > > doesn't notify its disablement, HD-audio would be blocked
> > > unnecessarily endlessly, waiting for the bind with i915.
> > > 
> > > This patch introduces a stub audio component binding when i915
> > > driver
> > > is loaded with KMS off like the boot options above.  Then i915
> > > driver
> > > still registers the slave component but with the new "disabled" ops
> > > flag, so that the master component (HD-audio) can know clearly the
> > > slave state.
> > > 
> > > Signed-off-by: Imre Deak <imre.deak@intel.com>
> > > Signed-off-by: Takashi Iwai <tiwai@suse.de>
> > > ---
> > >  drivers/gpu/drm/i915/i915_drv.c    | 34 +++++++++++++--------
> > >  drivers/gpu/drm/i915/intel_audio.c | 61
> > > ++++++++++++++++++++++++++++++++++++++
> > >  drivers/gpu/drm/i915/intel_drv.h   |  2 ++
> > >  include/drm/i915_component.h       |  5 ++++
> > >  4 files changed, 90 insertions(+), 12 deletions(-)
> > > 
> > > diff --git a/drivers/gpu/drm/i915/i915_drv.c
> > > b/drivers/gpu/drm/i915/i915_drv.c
> > > index 20e82008b8b6..21c6bac5468e 100644
> > > --- a/drivers/gpu/drm/i915/i915_drv.c
> > > +++ b/drivers/gpu/drm/i915/i915_drv.c
> > > @@ -950,6 +950,19 @@ static int i915_pci_probe(struct pci_dev
> > > *pdev, const struct pci_device_id *ent)
> > >  	struct intel_device_info *intel_info =
> > >  		(struct intel_device_info *) ent->driver_data;
> > >  
> > > +	if (!(driver.driver_features & DRIVER_MODESET)) {
> > > +		/*
> > > +		 * Notify the HDA driver so that it doesn't block
> > > waiting for
> > > +		 * i915 to become ready.
> > > +		 */
> > > +		i915_audio_component_stub_init(&pdev->dev);
> > > +
> > > +		/* Silently fail loading to not upset userspace.
> > > */
> > > +		DRM_DEBUG_DRIVER("KMS and UMS disabled.\n");
> > > +
> > > +		return 0;
> > > +	}
> > > +
> > 
> > Moving this here means we're actually going to bind to the device
> > even
> > w/o DRIVER_MODESET. Hopefully the fact that we don't register with
> > any
> > subsystems would make that OK. But since we need the actual device
> > for
> > the component stuff, I guess this is the only way.
> 
> Yes, the need for the device was the reason I moved this here. An
> alternative would be to add a miscdevice. I wanted to keep things
> simple and didn't see any problem of keeping the device bound, so chose
> this way.
> 
> One other thing I was thinking about is to also bind the stub component
> if the real probing failed to make things more consistent and avoid the
> longish timeout on the HDA side. This would also get messier with the
> miscdevice approach, since the probe error is not propagated to the
> caller of pci_register_driver(). If people don't see a problem with
> this I could add this in the next version.

Is a newer version already available?


thanks,

Takashi
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