[Mesa-dev] [PATCH 2/3] intel: Eliminate unneeded hiz resolves

[Chad Versace]

On creating a hiz miptree, we conservatively marked that each miptree
slice needed a hiz resolve. But the resolves are unneeded when creating
a non-texture miptree, so this patch removes them.

This eliminates one hiz resolve per each creation of a non-texture depth
miptree.  Hence, this eliminates many resolves when resizing a window.

Signed-off-by: Chad Versace <chad.versace at linux.intel.com>
---
 src/mesa/drivers/dri/intel/intel_fbo.c         |  4 ++-
 src/mesa/drivers/dri/intel/intel_mipmap_tree.c | 39 +++++++++++++++++---------
 src/mesa/drivers/dri/intel/intel_mipmap_tree.h |  3 +-
 3 files changed, 30 insertions(+), 16 deletions(-)

diff --git a/src/mesa/drivers/dri/intel/intel_fbo.c b/src/mesa/drivers/dri/intel/intel_fbo.c
index 3a610c2..ada0f69 100644
--- a/src/mesa/drivers/dri/intel/intel_fbo.c
+++ b/src/mesa/drivers/dri/intel/intel_fbo.c
@@ -538,7 +538,9 @@ intel_renderbuffer_update_wrapper(struct intel_context *intel,
 
    if (mt->hiz_mt == NULL &&
        intel->vtbl.is_hiz_depth_format(intel, rb->Format)) {
-      intel_miptree_alloc_hiz(intel, mt, 0 /* num_samples */);
+      intel_miptree_alloc_hiz(intel, mt,
+                              0 /*num_samples*/,
+                              true /*for_texture*/);
       if (!mt->hiz_mt)
 	 return false;
    }
diff --git a/src/mesa/drivers/dri/intel/intel_mipmap_tree.c b/src/mesa/drivers/dri/intel/intel_mipmap_tree.c
index 24cd9e9..143f2e3 100644
--- a/src/mesa/drivers/dri/intel/intel_mipmap_tree.c
+++ b/src/mesa/drivers/dri/intel/intel_mipmap_tree.c
@@ -467,7 +467,8 @@ intel_miptree_create_for_renderbuffer(struct intel_context *intel,
       goto fail;
 
    if (intel->vtbl.is_hiz_depth_format(intel, format)) {
-      ok = intel_miptree_alloc_hiz(intel, mt, num_samples);
+      ok = intel_miptree_alloc_hiz(intel, mt, num_samples,
+                                   false /*for_texture*/);
       if (!ok)
          goto fail;
    }
@@ -825,7 +826,8 @@ intel_miptree_alloc_mcs(struct intel_context *intel,
 bool
 intel_miptree_alloc_hiz(struct intel_context *intel,
 			struct intel_mipmap_tree *mt,
-                        GLuint num_samples)
+                        GLuint num_samples,
+                        bool for_texture)
 {
    assert(mt->hiz_mt == NULL);
    /* MSAA HiZ surfaces always use IMS layout. */
@@ -844,18 +846,27 @@ intel_miptree_alloc_hiz(struct intel_context *intel,
    if (!mt->hiz_mt)
       return false;
 
-   /* Mark that all slices need a HiZ resolve. */
-   struct intel_resolve_map *head = &mt->hiz_map;
-   for (int level = mt->first_level; level <= mt->last_level; ++level) {
-      for (int layer = 0; layer < mt->level[level].depth; ++layer) {
-	 head->next = malloc(sizeof(*head->next));
-	 head->next->prev = head;
-	 head->next->next = NULL;
-	 head = head->next;
-
-	 head->level = level;
-	 head->layer = layer;
-	 head->need = GEN6_HIZ_OP_HIZ_RESOLVE;
+   if (for_texture) {
+      /* Mark that all slices need a HiZ resolve. This is necessary for
+       * renderbuffers that wrap textures because the user may have previously
+       * uploaded texture data into the parent depth miptree.
+       *
+       * This is skipped for non-texture miptrees. In the non-texture case,
+       * the depth miptree and the hiz miptree are created together, and hence
+       * the content of each is undefined here.
+       */
+      struct intel_resolve_map *head = &mt->hiz_map;
+      for (int level = mt->first_level; level <= mt->last_level; ++level) {
+         for (int layer = 0; layer < mt->level[level].depth; ++layer) {
+            head->next = malloc(sizeof(*head->next));
+            head->next->prev = head;
+            head->next->next = NULL;
+            head = head->next;
+
+            head->level = level;
+            head->layer = layer;
+            head->need = GEN6_HIZ_OP_HIZ_RESOLVE;
+         }
       }
    }
 
diff --git a/src/mesa/drivers/dri/intel/intel_mipmap_tree.h b/src/mesa/drivers/dri/intel/intel_mipmap_tree.h
index 0d0e757..65743fd 100644
--- a/src/mesa/drivers/dri/intel/intel_mipmap_tree.h
+++ b/src/mesa/drivers/dri/intel/intel_mipmap_tree.h
@@ -503,7 +503,8 @@ intel_miptree_alloc_mcs(struct intel_context *intel,
 bool
 intel_miptree_alloc_hiz(struct intel_context *intel,
 			struct intel_mipmap_tree *mt,
-                        GLuint num_samples);
+                        GLuint num_samples,
+                        bool for_texture);
 
 void
 intel_miptree_slice_set_needs_hiz_resolve(struct intel_mipmap_tree *mt,
-- 
1.7.11.4