Mesa (master): i965/gen4: Remove redundant check for depth when rebasing stencil

[Topi Pohjolainen]

Module: Mesa
Branch: master
Commit: bb5d3fe96a5f4a2bcf0c8ea2b99853212e8c0247
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=bb5d3fe96a5f4a2bcf0c8ea2b99853212e8c0247

Author: Topi Pohjolainen <topi.pohjolainen at intel.com>
Date:   Fri May 19 10:39:21 2017 +0300

i965/gen4: Remove redundant check for depth when rebasing stencil

In case of gen < 6 stencil (if present) is always combined with
depth. Both stencil and depth attachments point to the same
physical surface.
Alignment workaround starts by considering depth and updates
stencil accordingly. Current logic continues with stencil and
in vain considers the case where depth would refer to different
surface than stencil.

Reviewed-by: Jason Ekstrand <jason at jlekstrand.net>
Signed-off-by: Topi Pohjolainen <topi.pohjolainen at intel.com>

---

 src/mesa/drivers/dri/i965/brw_misc_state.c | 63 ++++++------------------------
 1 file changed, 12 insertions(+), 51 deletions(-)

diff --git a/src/mesa/drivers/dri/i965/brw_misc_state.c b/src/mesa/drivers/dri/i965/brw_misc_state.c
index 111c09066c..9318822380 100644
--- a/src/mesa/drivers/dri/i965/brw_misc_state.c
+++ b/src/mesa/drivers/dri/i965/brw_misc_state.c
@@ -296,28 +296,14 @@ brw_workaround_depthstencil_alignment(struct brw_context *brw,
       }
 
       if (stencil_irb) {
-         stencil_mt = get_stencil_miptree(stencil_irb);
-         intel_miptree_get_image_offset(stencil_mt,
-                                        stencil_irb->mt_level,
-                                        stencil_irb->mt_layer,
-                                        &stencil_draw_x, &stencil_draw_y);
-         int stencil_tile_x = stencil_draw_x & tile_mask_x;
-         int stencil_tile_y = stencil_draw_y & tile_mask_y;
-
-         /* If stencil doesn't match depth, then we'll need to rebase stencil
-          * as well.  (if we hadn't decided to rebase stencil before, the
-          * post-stencil depth test will also rebase depth to try to match it
-          * up).
-          */
-         if (tile_x != stencil_tile_x ||
-             tile_y != stencil_tile_y) {
-            rebase_stencil = true;
-         }
+         assert(stencil_irb->mt == depth_irb->mt);
+         assert(stencil_irb->mt_level == depth_irb->mt_level);
+         assert(stencil_irb->mt_layer == depth_irb->mt_layer);
       }
    }
 
    /* If we have (just) stencil, check it for ignored low bits as well */
-   if (stencil_irb) {
+   if (!depth_irb && stencil_irb) {
       intel_miptree_get_image_offset(stencil_mt,
                                      stencil_irb->mt_level,
                                      stencil_irb->mt_layer,
@@ -335,6 +321,14 @@ brw_workaround_depthstencil_alignment(struct brw_context *brw,
    }
 
    if (rebase_stencil) {
+      /* If stencil needs rebase, there isn't a depth attachment and the
+       * combined depth-stencil is used for stencil only. Otherwise in case
+       * depth attachment is present both stencil and depth point to the same
+       * miptree. Rebase of depth is considered first updating stencil
+       * attachment accordingly - hence stencil is rebased only if there is no
+       * depth attachment.
+       */
+      assert(!depth_irb);
       perf_debug("HW workaround: blitting stencil level %d to a temporary "
                  "to fix alignment (stencil tile offset %d,%d)\n",
                  stencil_irb->mt_level, stencil_tile_x, stencil_tile_y);
@@ -348,39 +342,6 @@ brw_workaround_depthstencil_alignment(struct brw_context *brw,
                                      &stencil_draw_x, &stencil_draw_y);
       stencil_tile_x = stencil_draw_x & tile_mask_x;
       stencil_tile_y = stencil_draw_y & tile_mask_y;
-
-      if (depth_irb && depth_irb->mt == stencil_irb->mt) {
-         intel_miptree_reference(&depth_irb->mt, stencil_irb->mt);
-         intel_renderbuffer_set_draw_offset(depth_irb);
-      } else if (depth_irb && !rebase_depth) {
-         if (tile_x != stencil_tile_x ||
-             tile_y != stencil_tile_y) {
-            perf_debug("HW workaround: blitting depth level %d to a temporary "
-                       "to match stencil level %d alignment (depth tile offset "
-                       "%d,%d, stencil offset %d,%d)\n",
-                       depth_irb->mt_level,
-                       stencil_irb->mt_level,
-                       tile_x, tile_y,
-                       stencil_tile_x, stencil_tile_y);
-
-            intel_renderbuffer_move_to_temp(brw, depth_irb, invalidate_depth);
-
-            tile_x = depth_irb->draw_x & tile_mask_x;
-            tile_y = depth_irb->draw_y & tile_mask_y;
-
-            if (stencil_irb && stencil_irb->mt == depth_mt) {
-               intel_miptree_reference(&stencil_irb->mt, depth_irb->mt);
-               intel_renderbuffer_set_draw_offset(stencil_irb);
-            }
-
-            WARN_ONCE(stencil_tile_x != tile_x ||
-                      stencil_tile_y != tile_y,
-                      "Rebased stencil tile offset (%d,%d) doesn't match depth "
-                      "tile offset (%d,%d).\n",
-                      stencil_tile_x, stencil_tile_y,
-                      tile_x, tile_y);
-         }
-      }
    }
 
    if (!depth_irb) {