diff mbox

[RFC,07/12] drm/i915/config: Get workaround information from configuration.

Message ID 1423784498-11272-8-git-send-email-bob.j.paauwe@intel.com (mailing list archive)
State New, archived
Headers show

Commit Message

Paauwe, Bob J Feb. 12, 2015, 11:41 p.m. UTC
Add ability to parse a list of workarounds from the ACPI table.
Initially, this expects all workarounds listed to be valid and
they replace the hard coded list initialized in init_workarounds_ring().

The main benefit of this is the ability to add/remove workarounds
at runtime.  It may also be useful to "adjust" the workaround
list for a new GPU prior to fixed support being available in the
driver.

Signed-off-by: Bob Paauwe <bob.j.paauwe@intel.com>
---
 drivers/gpu/drm/i915/i915_drv.h     |   1 +
 drivers/gpu/drm/i915/intel_config.c | 101 +++++++++++++++++++++++++++++++++++-
 drivers/gpu/drm/i915/intel_drv.h    |   4 +-
 3 files changed, 104 insertions(+), 2 deletions(-)

Comments

Daniel Vetter Feb. 24, 2015, 1:51 p.m. UTC | #1
On Thu, Feb 12, 2015 at 03:41:33PM -0800, Bob Paauwe wrote:
> Add ability to parse a list of workarounds from the ACPI table.
> Initially, this expects all workarounds listed to be valid and
> they replace the hard coded list initialized in init_workarounds_ring().
> 
> The main benefit of this is the ability to add/remove workarounds
> at runtime.  It may also be useful to "adjust" the workaround
> list for a new GPU prior to fixed support being available in the
> driver.
> 
> Signed-off-by: Bob Paauwe <bob.j.paauwe@intel.com>

This one here freaks me out. We /should/ be fast enough with rolling out
workarounds through backports to stable kernels and product trees that
this shouldn't ever matter. And for a lot of workarounds this is too
limited since we also need to emit some of them to the ring on each engine
init or sometimes even context load.

As-is it looks a lot more like a backdoor to the driver to enable some
features no one wants to talk about in public ;-)
-Daniel

> ---
>  drivers/gpu/drm/i915/i915_drv.h     |   1 +
>  drivers/gpu/drm/i915/intel_config.c | 101 +++++++++++++++++++++++++++++++++++-
>  drivers/gpu/drm/i915/intel_drv.h    |   4 +-
>  3 files changed, 104 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 165091c..1580702 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -1656,6 +1656,7 @@ struct intel_config_info {
>  	struct list_head crtc_list;
>  	struct list_head connector_list;
>  	struct list_head plane_list;
> +	struct list_head wa_list;
>  };
>  
>  
> diff --git a/drivers/gpu/drm/i915/intel_config.c b/drivers/gpu/drm/i915/intel_config.c
> index fb495ed..ab14928 100644
> --- a/drivers/gpu/drm/i915/intel_config.c
> +++ b/drivers/gpu/drm/i915/intel_config.c
> @@ -214,6 +214,7 @@ void intel_config_init(struct drm_device *dev)
>  	INIT_LIST_HEAD(&info->crtc_list);
>  	INIT_LIST_HEAD(&info->connector_list);
>  	INIT_LIST_HEAD(&info->plane_list);
> +	INIT_LIST_HEAD(&info->wa_list);
>  
>  	handle = ACPI_HANDLE(dev->dev);
>  	if (!handle) {
> @@ -239,6 +240,7 @@ void intel_config_init(struct drm_device *dev)
>  #define i915_COMPONENT_CRTC "CRTC"
>  #define i915_COMPONENT_CONNECTOR "CNCT"
>  #define i915_COMPONENT_PLANE "PLNS"
> +#define i915_COMPONENT_WORKAROUND "WRKS"
>  
>  	/* Build lists */
>  	list_for_each_entry(component, &info->base.adev->children, node) {
> @@ -262,6 +264,9 @@ void intel_config_init(struct drm_device *dev)
>  				if (!alloc_new_node(cl, &info->crtc_list))
>  					goto bail;
>  			}
> +		} else if (strcmp(cname, i915_COMPONENT_WORKAROUND) == 0) {
> +			if (!alloc_new_node(cl, &info->wa_list))
> +				goto bail;
>  		}
>  	}
>  
> @@ -277,6 +282,8 @@ bail:
>  		kfree(new_node);
>  	list_for_each_entry_safe(new_node, tmp, &info->plane_list, node)
>  		kfree(new_node);
> +	list_for_each_entry_safe(new_node, tmp, &info->wa_list, node)
> +		kfree(new_node);
>  
>  	kfree(info);
>  	dev_priv->config_info = NULL;
> @@ -309,6 +316,8 @@ void intel_config_shutdown(struct drm_device *dev)
>  		kfree(n);
>  	list_for_each_entry_safe(n, tmp, &info->plane_list, node)
>  		kfree(n);
> +	list_for_each_entry_safe(n, tmp, &info->wa_list, node)
> +		kfree(n);
>  
>  	/* Unload any dynamically loaded ACPI property table */
>  	handle = ACPI_HANDLE(dev->dev);
> @@ -384,6 +393,8 @@ static struct list_head *cfg_type_to_list(struct intel_config_info *info,
>  		return &info->connector_list;
>  	case CFG_PLANE:
>  		return &info->plane_list;
> +	case CFG_WORKAROUND:
> +		return &info->wa_list;
>  	}
>  	return NULL;
>  }
> @@ -404,7 +415,6 @@ bool intel_config_get_integer(struct drm_i915_private *dev_priv,
>  	struct intel_config_info *info = dev_priv->config_info;
>  	struct intel_config_node *n;
>  	struct list_head *list;
> -	bool ret = false;
>  
>  	if (!info)
>  		return false;
> @@ -423,6 +433,95 @@ bool intel_config_get_integer(struct drm_i915_private *dev_priv,
>  	return false;
>  }
>  
> +
> +/*
> + * Use ACPI methods to enumerate the items in the WA list.
> + *
> + * The list from the ACPI table is inserted into the ring_init
> + * workaround table.  This could either over-wright any hard coded
> + * table or append to an existing hard coded table. Need to understand
> + * which way would make more sense.
> + */
> +bool intel_config_wa_add(struct drm_i915_private *dev_priv)
> +{
> +	struct intel_config_info *info = dev_priv->config_info;
> +	const union acpi_object *properties;
> +	const union acpi_object *prop, *name, *value;
> +	struct list_head *list;
> +	struct intel_config_node *n;
> +	int i;
> +	u32 idx;
> +	bool ret = false;
> +
> +	list = cfg_type_to_list(info, CFG_WORKAROUND);
> +	if (!list)
> +		return false;
> +
> +	list_for_each_entry(n, list, node) {
> +		properties = n->adev->data.properties;
> +		if (!properties)
> +			continue;
> +
> +		DRM_DEBUG_DRIVER("i915/config/wa: Found %d workarounds\n",
> +					properties->package.count);
> +
> +		for (i = 0; i < properties->package.count; i++) {
> +			prop = &properties->package.elements[i];
> +			name = &prop->package.elements[0];
> +			value = &prop->package.elements[1];
> +			ret = true;
> +
> +			/*
> +			 * Right now, it's assumed that any workarounds
> +			 * listed in the table should be added to the
> +			 * workaround array and applied. This could be a
> +			 * bad assumption.
> +			 *
> +			 * Might be better if the workaround table includes
> +			 * the PCI ID and check that before applying.
> +			 */
> +
> +			if ((value->package.count >= 2) &&
> +			    (value->type == ACPI_TYPE_PACKAGE)) {
> +				/*
> +				 * Package elements:
> +				 *   0 = workaround register
> +				 *   1 = register value
> +				 *   2 = mask
> +				 *   3 = mask enable vs disable bit (flags)
> +				 */
> +				idx = dev_priv->workarounds.count;
> +				if (WARN_ON(idx >= I915_MAX_WA_REGS))
> +					return ret;
> +
> +				dev_priv->workarounds.reg[idx].addr =
> +					(u32)value->package.elements[0].integer.value;
> +				dev_priv->workarounds.reg[idx].value =
> +					(u32)value->package.elements[1].integer.value;
> +
> +				if ((u32)value->package.elements[3].integer.value)
> +					dev_priv->workarounds.reg[idx].mask =
> +						_MASKED_BIT_ENABLE(
> +								(u32)value->package.elements[2].integer.value);
> +				else
> +					dev_priv->workarounds.reg[idx].mask =
> +						_MASKED_BIT_DISABLE(
> +								(u32)value->package.elements[2].integer.value);
> +
> +				dev_priv->workarounds.count++;
> +
> +				DRM_DEBUG_DRIVER("i915/config: WA %s = 0x%x, 0x%x, 0x%x\n",
> +					   name->string.pointer,
> +					   dev_priv->workarounds.reg[idx].addr,
> +					   dev_priv->workarounds.reg[idx].value,
> +					   dev_priv->workarounds.reg[idx].mask);
> +			}
> +		}
> +	}
> +
> +	return ret;
> +}
> +
>  /*
>   * Look up a drm property name in the configuration store and if
>   * found, return the value.
> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> index 4c81ee9..e2b4e09 100644
> --- a/drivers/gpu/drm/i915/intel_drv.h
> +++ b/drivers/gpu/drm/i915/intel_drv.h
> @@ -1265,11 +1265,13 @@ enum cfg_type {
>  	CFG_DRV,
>  	CFG_CRTC,
>  	CFG_CONNECTOR,
> -	CFG_PLANE
> +	CFG_PLANE,
> +	CFG_WORKAROUND
>  };
>  
>  void intel_config_init(struct drm_device *dev);
>  void intel_config_shutdown(struct drm_device *dev);
> +bool intel_config_wa_add(struct drm_i915_private *dev_priv);
>  bool intel_config_get_integer(struct drm_i915_private *dev_priv,
>  			  enum cfg_type cfg_type,
>  			  const char *name,
> -- 
> 2.1.0
> 
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx
Paauwe, Bob J Feb. 24, 2015, 5:54 p.m. UTC | #2
On Tue, 24 Feb 2015 14:51:31 +0100
Daniel Vetter <daniel@ffwll.ch> wrote:

> On Thu, Feb 12, 2015 at 03:41:33PM -0800, Bob Paauwe wrote:
> > Add ability to parse a list of workarounds from the ACPI table.
> > Initially, this expects all workarounds listed to be valid and
> > they replace the hard coded list initialized in init_workarounds_ring().
> > 
> > The main benefit of this is the ability to add/remove workarounds
> > at runtime.  It may also be useful to "adjust" the workaround
> > list for a new GPU prior to fixed support being available in the
> > driver.
> > 
> > Signed-off-by: Bob Paauwe <bob.j.paauwe@intel.com>
> 
> This one here freaks me out. We /should/ be fast enough with rolling out
> workarounds through backports to stable kernels and product trees that
> this shouldn't ever matter. And for a lot of workarounds this is too
> limited since we also need to emit some of them to the ring on each engine
> init or sometimes even context load.
> 
> As-is it looks a lot more like a backdoor to the driver to enable some
> features no one wants to talk about in public ;-)
> -Daniel

Yeah, I don't know that we have any valid use-case for this.  It
really is just an idea. Maybe a bad idea. It was something that looked
like it could map into the configuration space so I coded it up. 

I did think it might be useful if we could disable workarounds for early
steppings that may not be applicable for later steppings without the
need to release a new version of the driver.  As it sits, it doesn't
support this use-case so would need a bit more work. For some embedded
appliance type devices, customers are sometimes more willing to take a
configuration change than a new driver.

The patches for this should be easy to drop without effecting anything
else.

> 
> > ---
> >  drivers/gpu/drm/i915/i915_drv.h     |   1 +
> >  drivers/gpu/drm/i915/intel_config.c | 101 +++++++++++++++++++++++++++++++++++-
> >  drivers/gpu/drm/i915/intel_drv.h    |   4 +-
> >  3 files changed, 104 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> > index 165091c..1580702 100644
> > --- a/drivers/gpu/drm/i915/i915_drv.h
> > +++ b/drivers/gpu/drm/i915/i915_drv.h
> > @@ -1656,6 +1656,7 @@ struct intel_config_info {
> >  	struct list_head crtc_list;
> >  	struct list_head connector_list;
> >  	struct list_head plane_list;
> > +	struct list_head wa_list;
> >  };
> >  
> >  
> > diff --git a/drivers/gpu/drm/i915/intel_config.c b/drivers/gpu/drm/i915/intel_config.c
> > index fb495ed..ab14928 100644
> > --- a/drivers/gpu/drm/i915/intel_config.c
> > +++ b/drivers/gpu/drm/i915/intel_config.c
> > @@ -214,6 +214,7 @@ void intel_config_init(struct drm_device *dev)
> >  	INIT_LIST_HEAD(&info->crtc_list);
> >  	INIT_LIST_HEAD(&info->connector_list);
> >  	INIT_LIST_HEAD(&info->plane_list);
> > +	INIT_LIST_HEAD(&info->wa_list);
> >  
> >  	handle = ACPI_HANDLE(dev->dev);
> >  	if (!handle) {
> > @@ -239,6 +240,7 @@ void intel_config_init(struct drm_device *dev)
> >  #define i915_COMPONENT_CRTC "CRTC"
> >  #define i915_COMPONENT_CONNECTOR "CNCT"
> >  #define i915_COMPONENT_PLANE "PLNS"
> > +#define i915_COMPONENT_WORKAROUND "WRKS"
> >  
> >  	/* Build lists */
> >  	list_for_each_entry(component, &info->base.adev->children, node) {
> > @@ -262,6 +264,9 @@ void intel_config_init(struct drm_device *dev)
> >  				if (!alloc_new_node(cl, &info->crtc_list))
> >  					goto bail;
> >  			}
> > +		} else if (strcmp(cname, i915_COMPONENT_WORKAROUND) == 0) {
> > +			if (!alloc_new_node(cl, &info->wa_list))
> > +				goto bail;
> >  		}
> >  	}
> >  
> > @@ -277,6 +282,8 @@ bail:
> >  		kfree(new_node);
> >  	list_for_each_entry_safe(new_node, tmp, &info->plane_list, node)
> >  		kfree(new_node);
> > +	list_for_each_entry_safe(new_node, tmp, &info->wa_list, node)
> > +		kfree(new_node);
> >  
> >  	kfree(info);
> >  	dev_priv->config_info = NULL;
> > @@ -309,6 +316,8 @@ void intel_config_shutdown(struct drm_device *dev)
> >  		kfree(n);
> >  	list_for_each_entry_safe(n, tmp, &info->plane_list, node)
> >  		kfree(n);
> > +	list_for_each_entry_safe(n, tmp, &info->wa_list, node)
> > +		kfree(n);
> >  
> >  	/* Unload any dynamically loaded ACPI property table */
> >  	handle = ACPI_HANDLE(dev->dev);
> > @@ -384,6 +393,8 @@ static struct list_head *cfg_type_to_list(struct intel_config_info *info,
> >  		return &info->connector_list;
> >  	case CFG_PLANE:
> >  		return &info->plane_list;
> > +	case CFG_WORKAROUND:
> > +		return &info->wa_list;
> >  	}
> >  	return NULL;
> >  }
> > @@ -404,7 +415,6 @@ bool intel_config_get_integer(struct drm_i915_private *dev_priv,
> >  	struct intel_config_info *info = dev_priv->config_info;
> >  	struct intel_config_node *n;
> >  	struct list_head *list;
> > -	bool ret = false;
> >  
> >  	if (!info)
> >  		return false;
> > @@ -423,6 +433,95 @@ bool intel_config_get_integer(struct drm_i915_private *dev_priv,
> >  	return false;
> >  }
> >  
> > +
> > +/*
> > + * Use ACPI methods to enumerate the items in the WA list.
> > + *
> > + * The list from the ACPI table is inserted into the ring_init
> > + * workaround table.  This could either over-wright any hard coded
> > + * table or append to an existing hard coded table. Need to understand
> > + * which way would make more sense.
> > + */
> > +bool intel_config_wa_add(struct drm_i915_private *dev_priv)
> > +{
> > +	struct intel_config_info *info = dev_priv->config_info;
> > +	const union acpi_object *properties;
> > +	const union acpi_object *prop, *name, *value;
> > +	struct list_head *list;
> > +	struct intel_config_node *n;
> > +	int i;
> > +	u32 idx;
> > +	bool ret = false;
> > +
> > +	list = cfg_type_to_list(info, CFG_WORKAROUND);
> > +	if (!list)
> > +		return false;
> > +
> > +	list_for_each_entry(n, list, node) {
> > +		properties = n->adev->data.properties;
> > +		if (!properties)
> > +			continue;
> > +
> > +		DRM_DEBUG_DRIVER("i915/config/wa: Found %d workarounds\n",
> > +					properties->package.count);
> > +
> > +		for (i = 0; i < properties->package.count; i++) {
> > +			prop = &properties->package.elements[i];
> > +			name = &prop->package.elements[0];
> > +			value = &prop->package.elements[1];
> > +			ret = true;
> > +
> > +			/*
> > +			 * Right now, it's assumed that any workarounds
> > +			 * listed in the table should be added to the
> > +			 * workaround array and applied. This could be a
> > +			 * bad assumption.
> > +			 *
> > +			 * Might be better if the workaround table includes
> > +			 * the PCI ID and check that before applying.
> > +			 */
> > +
> > +			if ((value->package.count >= 2) &&
> > +			    (value->type == ACPI_TYPE_PACKAGE)) {
> > +				/*
> > +				 * Package elements:
> > +				 *   0 = workaround register
> > +				 *   1 = register value
> > +				 *   2 = mask
> > +				 *   3 = mask enable vs disable bit (flags)
> > +				 */
> > +				idx = dev_priv->workarounds.count;
> > +				if (WARN_ON(idx >= I915_MAX_WA_REGS))
> > +					return ret;
> > +
> > +				dev_priv->workarounds.reg[idx].addr =
> > +					(u32)value->package.elements[0].integer.value;
> > +				dev_priv->workarounds.reg[idx].value =
> > +					(u32)value->package.elements[1].integer.value;
> > +
> > +				if ((u32)value->package.elements[3].integer.value)
> > +					dev_priv->workarounds.reg[idx].mask =
> > +						_MASKED_BIT_ENABLE(
> > +								(u32)value->package.elements[2].integer.value);
> > +				else
> > +					dev_priv->workarounds.reg[idx].mask =
> > +						_MASKED_BIT_DISABLE(
> > +								(u32)value->package.elements[2].integer.value);
> > +
> > +				dev_priv->workarounds.count++;
> > +
> > +				DRM_DEBUG_DRIVER("i915/config: WA %s = 0x%x, 0x%x, 0x%x\n",
> > +					   name->string.pointer,
> > +					   dev_priv->workarounds.reg[idx].addr,
> > +					   dev_priv->workarounds.reg[idx].value,
> > +					   dev_priv->workarounds.reg[idx].mask);
> > +			}
> > +		}
> > +	}
> > +
> > +	return ret;
> > +}
> > +
> >  /*
> >   * Look up a drm property name in the configuration store and if
> >   * found, return the value.
> > diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> > index 4c81ee9..e2b4e09 100644
> > --- a/drivers/gpu/drm/i915/intel_drv.h
> > +++ b/drivers/gpu/drm/i915/intel_drv.h
> > @@ -1265,11 +1265,13 @@ enum cfg_type {
> >  	CFG_DRV,
> >  	CFG_CRTC,
> >  	CFG_CONNECTOR,
> > -	CFG_PLANE
> > +	CFG_PLANE,
> > +	CFG_WORKAROUND
> >  };
> >  
> >  void intel_config_init(struct drm_device *dev);
> >  void intel_config_shutdown(struct drm_device *dev);
> > +bool intel_config_wa_add(struct drm_i915_private *dev_priv);
> >  bool intel_config_get_integer(struct drm_i915_private *dev_priv,
> >  			  enum cfg_type cfg_type,
> >  			  const char *name,
> > -- 
> > 2.1.0
> > 
> > _______________________________________________
> > Intel-gfx mailing list
> > Intel-gfx@lists.freedesktop.org
> > http://lists.freedesktop.org/mailman/listinfo/intel-gfx
>
diff mbox

Patch

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 165091c..1580702 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1656,6 +1656,7 @@  struct intel_config_info {
 	struct list_head crtc_list;
 	struct list_head connector_list;
 	struct list_head plane_list;
+	struct list_head wa_list;
 };
 
 
diff --git a/drivers/gpu/drm/i915/intel_config.c b/drivers/gpu/drm/i915/intel_config.c
index fb495ed..ab14928 100644
--- a/drivers/gpu/drm/i915/intel_config.c
+++ b/drivers/gpu/drm/i915/intel_config.c
@@ -214,6 +214,7 @@  void intel_config_init(struct drm_device *dev)
 	INIT_LIST_HEAD(&info->crtc_list);
 	INIT_LIST_HEAD(&info->connector_list);
 	INIT_LIST_HEAD(&info->plane_list);
+	INIT_LIST_HEAD(&info->wa_list);
 
 	handle = ACPI_HANDLE(dev->dev);
 	if (!handle) {
@@ -239,6 +240,7 @@  void intel_config_init(struct drm_device *dev)
 #define i915_COMPONENT_CRTC "CRTC"
 #define i915_COMPONENT_CONNECTOR "CNCT"
 #define i915_COMPONENT_PLANE "PLNS"
+#define i915_COMPONENT_WORKAROUND "WRKS"
 
 	/* Build lists */
 	list_for_each_entry(component, &info->base.adev->children, node) {
@@ -262,6 +264,9 @@  void intel_config_init(struct drm_device *dev)
 				if (!alloc_new_node(cl, &info->crtc_list))
 					goto bail;
 			}
+		} else if (strcmp(cname, i915_COMPONENT_WORKAROUND) == 0) {
+			if (!alloc_new_node(cl, &info->wa_list))
+				goto bail;
 		}
 	}
 
@@ -277,6 +282,8 @@  bail:
 		kfree(new_node);
 	list_for_each_entry_safe(new_node, tmp, &info->plane_list, node)
 		kfree(new_node);
+	list_for_each_entry_safe(new_node, tmp, &info->wa_list, node)
+		kfree(new_node);
 
 	kfree(info);
 	dev_priv->config_info = NULL;
@@ -309,6 +316,8 @@  void intel_config_shutdown(struct drm_device *dev)
 		kfree(n);
 	list_for_each_entry_safe(n, tmp, &info->plane_list, node)
 		kfree(n);
+	list_for_each_entry_safe(n, tmp, &info->wa_list, node)
+		kfree(n);
 
 	/* Unload any dynamically loaded ACPI property table */
 	handle = ACPI_HANDLE(dev->dev);
@@ -384,6 +393,8 @@  static struct list_head *cfg_type_to_list(struct intel_config_info *info,
 		return &info->connector_list;
 	case CFG_PLANE:
 		return &info->plane_list;
+	case CFG_WORKAROUND:
+		return &info->wa_list;
 	}
 	return NULL;
 }
@@ -404,7 +415,6 @@  bool intel_config_get_integer(struct drm_i915_private *dev_priv,
 	struct intel_config_info *info = dev_priv->config_info;
 	struct intel_config_node *n;
 	struct list_head *list;
-	bool ret = false;
 
 	if (!info)
 		return false;
@@ -423,6 +433,95 @@  bool intel_config_get_integer(struct drm_i915_private *dev_priv,
 	return false;
 }
 
+
+/*
+ * Use ACPI methods to enumerate the items in the WA list.
+ *
+ * The list from the ACPI table is inserted into the ring_init
+ * workaround table.  This could either over-wright any hard coded
+ * table or append to an existing hard coded table. Need to understand
+ * which way would make more sense.
+ */
+bool intel_config_wa_add(struct drm_i915_private *dev_priv)
+{
+	struct intel_config_info *info = dev_priv->config_info;
+	const union acpi_object *properties;
+	const union acpi_object *prop, *name, *value;
+	struct list_head *list;
+	struct intel_config_node *n;
+	int i;
+	u32 idx;
+	bool ret = false;
+
+	list = cfg_type_to_list(info, CFG_WORKAROUND);
+	if (!list)
+		return false;
+
+	list_for_each_entry(n, list, node) {
+		properties = n->adev->data.properties;
+		if (!properties)
+			continue;
+
+		DRM_DEBUG_DRIVER("i915/config/wa: Found %d workarounds\n",
+					properties->package.count);
+
+		for (i = 0; i < properties->package.count; i++) {
+			prop = &properties->package.elements[i];
+			name = &prop->package.elements[0];
+			value = &prop->package.elements[1];
+			ret = true;
+
+			/*
+			 * Right now, it's assumed that any workarounds
+			 * listed in the table should be added to the
+			 * workaround array and applied. This could be a
+			 * bad assumption.
+			 *
+			 * Might be better if the workaround table includes
+			 * the PCI ID and check that before applying.
+			 */
+
+			if ((value->package.count >= 2) &&
+			    (value->type == ACPI_TYPE_PACKAGE)) {
+				/*
+				 * Package elements:
+				 *   0 = workaround register
+				 *   1 = register value
+				 *   2 = mask
+				 *   3 = mask enable vs disable bit (flags)
+				 */
+				idx = dev_priv->workarounds.count;
+				if (WARN_ON(idx >= I915_MAX_WA_REGS))
+					return ret;
+
+				dev_priv->workarounds.reg[idx].addr =
+					(u32)value->package.elements[0].integer.value;
+				dev_priv->workarounds.reg[idx].value =
+					(u32)value->package.elements[1].integer.value;
+
+				if ((u32)value->package.elements[3].integer.value)
+					dev_priv->workarounds.reg[idx].mask =
+						_MASKED_BIT_ENABLE(
+								(u32)value->package.elements[2].integer.value);
+				else
+					dev_priv->workarounds.reg[idx].mask =
+						_MASKED_BIT_DISABLE(
+								(u32)value->package.elements[2].integer.value);
+
+				dev_priv->workarounds.count++;
+
+				DRM_DEBUG_DRIVER("i915/config: WA %s = 0x%x, 0x%x, 0x%x\n",
+					   name->string.pointer,
+					   dev_priv->workarounds.reg[idx].addr,
+					   dev_priv->workarounds.reg[idx].value,
+					   dev_priv->workarounds.reg[idx].mask);
+			}
+		}
+	}
+
+	return ret;
+}
+
 /*
  * Look up a drm property name in the configuration store and if
  * found, return the value.
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 4c81ee9..e2b4e09 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -1265,11 +1265,13 @@  enum cfg_type {
 	CFG_DRV,
 	CFG_CRTC,
 	CFG_CONNECTOR,
-	CFG_PLANE
+	CFG_PLANE,
+	CFG_WORKAROUND
 };
 
 void intel_config_init(struct drm_device *dev);
 void intel_config_shutdown(struct drm_device *dev);
+bool intel_config_wa_add(struct drm_i915_private *dev_priv);
 bool intel_config_get_integer(struct drm_i915_private *dev_priv,
 			  enum cfg_type cfg_type,
 			  const char *name,