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: Paulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

1 files changed, 4 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index d4240dba16ff..ffd4ab111957 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -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);