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Commit a9da512b authored by Paulo Zanoni's avatar Paulo Zanoni Committed by Daniel Vetter
Browse files

drm/i915: avoid the last 8mb of stolen on BDW/SKL 



The FBC hardware for these platforms doesn't have access to the
bios_reserved range, so it always assumes the maximum (8mb) is used.
So avoid this range while allocating.

This solves a bunch of FIFO underruns that happen if you end up
putting the CFB in that memory range. On my machine, with 32mb of
stolen, I need a 2560x1440 mode for that.

Testcase: igt/kms_frontbuffer_tracking/fbc-* (given the right setup)
Signed-off-by: default avatarPaulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: default avatarVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
parent adf70c65

drivers/gpu/drm/i915/i915_drv.h

+4 −0
Original line number Diff line number Diff line
@@ -3175,6 +3175,10 @@ static inline void i915_gem_chipset_flush(struct drm_device *dev) 
int i915_gem_stolen_insert_node(struct drm_i915_private *dev_priv,

				struct drm_mm_node *node, u64 size,

				unsigned alignment);

int i915_gem_stolen_insert_node_in_range(struct drm_i915_private *dev_priv,

					 struct drm_mm_node *node, u64 size,

					 unsigned alignment, u64 start,

					 u64 end);

void i915_gem_stolen_remove_node(struct drm_i915_private *dev_priv,

				 struct drm_mm_node *node);

int i915_gem_init_stolen(struct drm_device *dev);

drivers/gpu/drm/i915/i915_gem_gtt.h

+1 −0
Original line number Diff line number Diff line
@@ -341,6 +341,7 @@ struct i915_gtt { 
	struct i915_address_space base;



	size_t stolen_size;		/* Total size of stolen memory */

	size_t stolen_usable_size;	/* Total size minus BIOS reserved */

	u64 mappable_end;		/* End offset that we can CPU map */

	struct io_mapping *mappable;	/* Mapping to our CPU mappable region */

	phys_addr_t mappable_base;	/* PA of our GMADR */

drivers/gpu/drm/i915/i915_gem_stolen.c

+19 −7
Original line number Diff line number Diff line
@@ -42,9 +42,9 @@ 
 * for is a boon.

 */



int i915_gem_stolen_insert_node(struct drm_i915_private *dev_priv,

int i915_gem_stolen_insert_node_in_range(struct drm_i915_private *dev_priv,

					 struct drm_mm_node *node, u64 size,

				unsigned alignment)

					 unsigned alignment, u64 start, u64 end)

{

	int ret;
@@ -52,13 +52,23 @@ int i915_gem_stolen_insert_node(struct drm_i915_private *dev_priv, 
		return -ENODEV;



	mutex_lock(&dev_priv->mm.stolen_lock);

	ret = drm_mm_insert_node(&dev_priv->mm.stolen, node, size, alignment,

	ret = drm_mm_insert_node_in_range(&dev_priv->mm.stolen, node, size,

					  alignment, start, end,

					  DRM_MM_SEARCH_DEFAULT);

	mutex_unlock(&dev_priv->mm.stolen_lock);



	return ret;

}



int i915_gem_stolen_insert_node(struct drm_i915_private *dev_priv,

				struct drm_mm_node *node, u64 size,

				unsigned alignment)

{

	return i915_gem_stolen_insert_node_in_range(dev_priv, node, size,

					alignment, 0,

					dev_priv->gtt.stolen_usable_size);

}



void i915_gem_stolen_remove_node(struct drm_i915_private *dev_priv,

				 struct drm_mm_node *node)

{
@@ -355,9 +365,11 @@ int i915_gem_init_stolen(struct drm_device *dev) 
		      dev_priv->gtt.stolen_size >> 10,

		      (dev_priv->gtt.stolen_size - reserved_total) >> 10);



	dev_priv->gtt.stolen_usable_size = dev_priv->gtt.stolen_size -

					   reserved_total;



	/* Basic memrange allocator for stolen space */

	drm_mm_init(&dev_priv->mm.stolen, 0, dev_priv->gtt.stolen_size -

		    reserved_total);

	drm_mm_init(&dev_priv->mm.stolen, 0, dev_priv->gtt.stolen_usable_size);



	return 0;

}

drivers/gpu/drm/i915/intel_fbc.c

+14 −2
Original line number Diff line number Diff line
@@ -551,6 +551,16 @@ static int find_compression_threshold(struct drm_i915_private *dev_priv, 
{

	int compression_threshold = 1;

	int ret;

	u64 end;



	/* The FBC hardware for BDW/SKL doesn't have access to the stolen

	 * reserved range size, so it always assumes the maximum (8mb) is used.

	 * If we enable FBC using a CFB on that memory range we'll get FIFO

	 * underruns, even if that range is not reserved by the BIOS. */

	if (IS_BROADWELL(dev_priv) || IS_SKYLAKE(dev_priv))

		end = dev_priv->gtt.stolen_size - 8 * 1024 * 1024;

	else

		end = dev_priv->gtt.stolen_usable_size;



	/* HACK: This code depends on what we will do in *_enable_fbc. If that

	 * code changes, this code needs to change as well.
@@ -560,7 +570,8 @@ static int find_compression_threshold(struct drm_i915_private *dev_priv, 
	 */



	/* Try to over-allocate to reduce reallocations and fragmentation. */

	ret = i915_gem_stolen_insert_node(dev_priv, node, size <<= 1, 4096);

	ret = i915_gem_stolen_insert_node_in_range(dev_priv, node, size <<= 1,

						   4096, 0, end);

	if (ret == 0)

		return compression_threshold;
@@ -570,7 +581,8 @@ static int find_compression_threshold(struct drm_i915_private *dev_priv, 
	    (fb_cpp == 2 && compression_threshold == 2))

		return 0;



	ret = i915_gem_stolen_insert_node(dev_priv, node, size >>= 1, 4096);

	ret = i915_gem_stolen_insert_node_in_range(dev_priv, node, size >>= 1,

						   4096, 0, end);

	if (ret && INTEL_INFO(dev_priv)->gen <= 4) {

		return 0;

	} else if (ret) {