i965: Implement HiZ resolves on Broadwell.

Broadwell's 3DSTATE_WM_HZ_OP packet makes this much easier.

Instead of programming the whole pipeline, we simply have to emit the
depth/stencil packets, a state override, and a pipe control.  Then
arrange for the state to be put back.  This is easily done from a single
function.

v2: Use minify(mt->logical_{width,height}0, level) in 3DSTATE_WM_HZ_OP
    instead of intel_mipmap_level's width/height fields.  Those were
    based on the physical width/height, and thus wrong for MSAA buffers.
    Eric also deleted those fields.

v3: Use 0xFFFF as the sample mask regardless of what the user set (as
    this operation is unrelated); set the drawing rectangle to the
    miplevel being operated on, rather than the whole surface; remove
    unnecessary MAX2(..., 1) around mt->logical_depth0 (all suggested
    by Eric Anholt).

Signed-off-by: Kenneth Graunke <[email protected]>
Reviewed-by: Eric Anholt <[email protected]>

3 files changed, 113 insertions, 2 deletions

diff --git a/src/mesa/drivers/dri/i965/brw_blorp.cpp b/src/mesa/drivers/dri/i965/brw_blorp.cpp
index 79800131e00..5192fd33dfb 100644
--- a/src/mesa/drivers/dri/i965/brw_blorp.cpp
+++ b/src/mesa/drivers/dri/i965/brw_blorp.cpp
@@ -195,8 +195,12 @@ intel_hiz_exec(struct brw_context *brw, struct intel_mipmap_tree *mt,
    DBG("%s %s to mt %p level %d layer %d\n",
        __FUNCTION__, opname, mt, level, layer);
 
-   brw_hiz_op_params params(mt, level, layer, op);
-   brw_blorp_exec(brw, &params);
+   if (brw->gen >= 8) {
+      gen8_hiz_exec(brw, mt, level, layer, op);
+   } else {
+      brw_hiz_op_params params(mt, level, layer, op);
+      brw_blorp_exec(brw, &params);
+   }
 }
 
 } /* extern "C" */
diff --git a/src/mesa/drivers/dri/i965/brw_context.h b/src/mesa/drivers/dri/i965/brw_context.h
index cf0fe98cd15..c107683cb34 100644
--- a/src/mesa/drivers/dri/i965/brw_context.h
+++ b/src/mesa/drivers/dri/i965/brw_context.h
@@ -61,6 +61,7 @@ extern "C" {
 #include "intel_debug.h"
 #include "intel_screen.h"
 #include "intel_tex_obj.h"
+#include "intel_resolve_map.h"
 
 /* Glossary:
  *
@@ -1891,6 +1892,9 @@ gen8_emit_depth_stencil_hiz(struct brw_context *brw,
                             uint32_t width, uint32_t height,
                             uint32_t tile_x, uint32_t tile_y);
 
+void gen8_hiz_exec(struct brw_context *brw, struct intel_mipmap_tree *mt,
+                   unsigned int level, unsigned int layer, enum gen6_hiz_op op);
+
 extern const GLuint prim_to_hw_prim[GL_TRIANGLE_STRIP_ADJACENCY+1];
 
 void
diff --git a/src/mesa/drivers/dri/i965/gen8_depth_state.c b/src/mesa/drivers/dri/i965/gen8_depth_state.c
index f30ff289c72..379a2c34905 100644
--- a/src/mesa/drivers/dri/i965/gen8_depth_state.c
+++ b/src/mesa/drivers/dri/i965/gen8_depth_state.c
@@ -203,3 +203,106 @@ gen8_emit_depth_stencil_hiz(struct brw_context *brw,
                       brw->depthstencil.stencil_offset,
                       hiz, width, height, depth, lod, min_array_element);
 }
+
+/**
+ * Emit packets to perform a depth/HiZ resolve or fast depth/stencil clear.
+ *
+ * See the "Optimized Depth Buffer Clear and/or Stencil Buffer Clear" section
+ * of the hardware documentation for details.
+ */
+void
+gen8_hiz_exec(struct brw_context *brw, struct intel_mipmap_tree *mt,
+              unsigned int level, unsigned int layer, enum gen6_hiz_op op)
+{
+   if (op == GEN6_HIZ_OP_NONE)
+      return;
+
+   assert(mt->first_level == 0);
+   assert(mt->logical_depth0 >= 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.
+    * - If needed, emit 3DSTATE_DRAWING_RECTANGLE.
+    * - Emit 3DSTATE_WM_HZ_OP with a bit set for the particular operation.
+    * - Do a special PIPE_CONTROL to trigger an implicit rectangle primitive.
+    * - Emit 3DSTATE_WM_HZ_OP with no bits set to return to normal rendering.
+    */
+   emit_depth_packets(brw, mt,
+                      brw_depth_format(brw, mt->format),
+                      BRW_SURFACE_2D,
+                      true, /* depth writes */
+                      NULL, false, 0, /* no stencil for now */
+                      true, /* hiz */
+                      mt->logical_width0,
+                      mt->logical_height0,
+                      mt->logical_depth0,
+                      level,
+                      layer); /* min_array_element */
+
+   unsigned rect_width = minify(mt->logical_width0, level);
+   unsigned rect_height = minify(mt->logical_height0, level);
+
+   BEGIN_BATCH(4);
+   OUT_BATCH(_3DSTATE_DRAWING_RECTANGLE << 16 | (4 - 2));
+   OUT_BATCH(0);
+   OUT_BATCH(((rect_width - 1) & 0xffff) | ((rect_height - 1) << 16));
+   OUT_BATCH(0);
+   ADVANCE_BATCH();
+
+   /* Emit 3DSTATE_WM_HZ_OP to override pipeline state for the particular
+    * resolve or clear operation we want to perform.
+    */
+   uint32_t dw1 = 0;
+
+   switch (op) {
+   case GEN6_HIZ_OP_DEPTH_RESOLVE:
+      dw1 |= GEN8_WM_HZ_DEPTH_RESOLVE;
+      break;
+   case GEN6_HIZ_OP_HIZ_RESOLVE:
+      dw1 |= GEN8_WM_HZ_HIZ_RESOLVE;
+      break;
+   case GEN6_HIZ_OP_DEPTH_CLEAR:
+      dw1 |= GEN8_WM_HZ_DEPTH_CLEAR;
+      break;
+   case GEN6_HIZ_OP_NONE:
+      assert(!"Should not get here.");
+   }
+
+   if (mt->num_samples > 0)
+      dw1 |= SET_FIELD(ffs(mt->num_samples) - 1, GEN8_WM_HZ_NUM_SAMPLES);
+
+   BEGIN_BATCH(5);
+   OUT_BATCH(_3DSTATE_WM_HZ_OP << 16 | (5 - 2));
+   OUT_BATCH(dw1);
+   OUT_BATCH(0);
+   OUT_BATCH(SET_FIELD(rect_width, GEN8_WM_HZ_CLEAR_RECTANGLE_X_MAX) |
+             SET_FIELD(rect_height, GEN8_WM_HZ_CLEAR_RECTANGLE_Y_MAX));
+   OUT_BATCH(SET_FIELD(0xFFFF, GEN8_WM_HZ_SAMPLE_MASK));
+   ADVANCE_BATCH();
+
+   /* Emit a PIPE_CONTROL with "Post-Sync Operation" set to "Write Immediate
+    * Data", and no other bits set.  This causes 3DSTATE_WM_HZ_OP's state to
+    * take effect, and spawns a rectangle primitive.
+    */
+   brw_emit_pipe_control_write(brw,
+                               PIPE_CONTROL_WRITE_IMMEDIATE,
+                               brw->batch.workaround_bo, 0, 0, 0);
+
+   /* Emit 3DSTATE_WM_HZ_OP again to disable the state overrides. */
+   BEGIN_BATCH(5);
+   OUT_BATCH(_3DSTATE_WM_HZ_OP << 16 | (5 - 2));
+   OUT_BATCH(0);
+   OUT_BATCH(0);
+   OUT_BATCH(0);
+   OUT_BATCH(0);
+   ADVANCE_BATCH();
+
+   /* We've clobbered all of the depth packets, and the drawing rectangle,
+    * so we need to ensure those packets are re-emitted before the next
+    * primitive.
+    *
+    * Setting _NEW_DEPTH and _NEW_BUFFERS covers it, but is rather overkill.
+    */
+   brw->state.dirty.mesa |= _NEW_DEPTH | _NEW_BUFFERS;
+}