drm/i915/gen9+: Kill off hw_ddb from intel_crtc.

dev_priv->hw_ddb is only used by skl_update_crtcs, but the ddb
allocation for each pipe is calculated in crtc_state.

We can rid of the global member by looking at crtc_state.
Do this by saving all active old ddb allocations from the old crtc_state
in an array, and then point them to the new allocation every time we update
a crtc.

This will allow us to keep track of the intermediate ddb allocations,
which is what hw_ddb was previously used for. With hw_ddb gone all
SKL-style watermark values are properly maintained only in crtc_state.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1478609742-13603-5-git-send-email-maarten.lankhorst@linux.intel.com
[mlankhorst: Reword commit message.]
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 3b2c567..0be407e 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -727,9 +727,6 @@ struct intel_crtc {
 		bool cxsr_allowed;
 	} wm;
 
-	/* gen9+: ddb allocation currently being used */
-	struct skl_ddb_entry hw_ddb;
-
 	int scanline_offset;
 
 	struct {
@@ -1739,11 +1736,9 @@ int intel_enable_sagv(struct drm_i915_private *dev_priv);
 int intel_disable_sagv(struct drm_i915_private *dev_priv);
 bool skl_wm_level_equals(const struct skl_wm_level *l1,
 			 const struct skl_wm_level *l2);
-bool skl_ddb_allocation_equals(const struct skl_ddb_allocation *old,
-			       const struct skl_ddb_allocation *new,
-			       enum pipe pipe);
-bool skl_ddb_allocation_overlaps(struct drm_atomic_state *state,
-				 struct intel_crtc *intel_crtc);
+bool skl_ddb_allocation_overlaps(const struct skl_ddb_entry **entries,
+				 const struct skl_ddb_entry *ddb,
+				 int ignore);
 uint32_t ilk_pipe_pixel_rate(const struct intel_crtc_state *pipe_config);
 bool ilk_disable_lp_wm(struct drm_device *dev);
 int sanitize_rc6_option(struct drm_i915_private *dev_priv, int enable_rc6);