Mesa (master): i965: Use 8x4 aligned rectangles for HiZ operations on Broadwell.

[Kenneth Graunke]

Module: Mesa
Branch: master
Commit: 49659ad90c501ae584b7d76ca98f35a8f57d40fe
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=49659ad90c501ae584b7d76ca98f35a8f57d40fe

Author: Kenneth Graunke <kenneth at whitecape.org>
Date:   Fri Jun 13 15:26:40 2014 -0700

i965: Use 8x4 aligned rectangles for HiZ operations on Broadwell.

Like on Haswell, we need to use 8x4 aligned rectangle primitives for
hierarchical depth buffer resolves and depth clears.  See the comments
in brw_blorp.cpp's brw_hiz_op_params() constructor.  (The Broadwell
documentation confirms that this is still necessary.)

This patch makes the Broadwell code follow the same behavior as Chad and
Jordan's Gen7 BLORP code.  Based on a patch by Topi Pohjolainen.

This fixes es3conform's framebuffer_blit_functionality_scissor_blit
test, with no Piglit regressions.

Signed-off-by: Kenneth Graunke <kenneth at whitecape.org>
Reviewed-by: Jordan Justen <jordan.l.justen at intel.com>
Cc: "10.2" <mesa-stable at lists.freedesktop.org>

---

 src/mesa/drivers/dri/i965/gen8_depth_state.c |   20 ++++++++++++++++----
 1 file changed, 16 insertions(+), 4 deletions(-)

diff --git a/src/mesa/drivers/dri/i965/gen8_depth_state.c b/src/mesa/drivers/dri/i965/gen8_depth_state.c
index 8c70c62..f538d23 100644
--- a/src/mesa/drivers/dri/i965/gen8_depth_state.c
+++ b/src/mesa/drivers/dri/i965/gen8_depth_state.c
@@ -225,6 +225,13 @@ gen8_hiz_exec(struct brw_context *brw, struct intel_mipmap_tree *mt,
    assert(mt->first_level == 0);
    assert(mt->logical_depth0 >= 1);
 
+   /* If we're operating on LOD 0, align to 8x4 to meet the alignment
+    * requirements for most HiZ operations.  Otherwise, use the actual size
+    * to allow the hardware to calculate the miplevel offsets correctly.
+    */
+   uint32_t surface_width  = ALIGN(mt->logical_width0,  level == 0 ? 8 : 1);
+   uint32_t surface_height = ALIGN(mt->logical_height0, level == 0 ? 4 : 1);
+
    /* The basic algorithm is:
     * - If needed, emit 3DSTATE_{DEPTH,HIER_DEPTH,STENCIL}_BUFFER and
     *   3DSTATE_CLEAR_PARAMS packets to set up the relevant buffers.
@@ -239,14 +246,19 @@ gen8_hiz_exec(struct brw_context *brw, struct intel_mipmap_tree *mt,
                       true, /* depth writes */
                       NULL, false, 0, /* no stencil for now */
                       true, /* hiz */
-                      mt->logical_width0,
-                      mt->logical_height0,
+                      surface_width,
+                      surface_height,
                       mt->logical_depth0,
                       level,
                       layer); /* min_array_element */
 
-   unsigned rect_width = minify(mt->logical_width0, level);
-   unsigned rect_height = minify(mt->logical_height0, level);
+   /* Depth buffer clears and HiZ resolves must use an 8x4 aligned rectangle.
+    * Note that intel_miptree_level_enable_hiz disables HiZ for miplevels > 0
+    * which aren't 8x4 aligned, so expanding the size is safe - it'll just
+    * draw into empty padding space.
+    */
+   unsigned rect_width = ALIGN(minify(mt->logical_width0, level), 8);
+   unsigned rect_height = ALIGN(minify(mt->logical_height0, level), 4);
 
    BEGIN_BATCH(4);
    OUT_BATCH(_3DSTATE_DRAWING_RECTANGLE << 16 | (4 - 2));