[Mesa-dev] [PATCH 15/17] i965/gen6: Force tile alignment for each stencil/hiz LOD

[Jordan Justen]

Gen6 doesn't support multiple miplevels for hiz and stencil.

Therefore, we must point to the LOD directly during rendering.

But, we also have removed the tile offsets from normal depth surfaces,
so we need to align each LOD to a tile boundary for hiz and stencil.

Signed-off-by: Jordan Justen <jordan.l.justen at intel.com>
---
 src/mesa/drivers/dri/i965/brw_tex_layout.c | 39 +++++++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 3 deletions(-)

diff --git a/src/mesa/drivers/dri/i965/brw_tex_layout.c b/src/mesa/drivers/dri/i965/brw_tex_layout.c
index 9d248cb..b6fed4d 100644
--- a/src/mesa/drivers/dri/i965/brw_tex_layout.c
+++ b/src/mesa/drivers/dri/i965/brw_tex_layout.c
@@ -35,6 +35,7 @@
 #include "intel_mipmap_tree.h"
 #include "brw_context.h"
 #include "main/macros.h"
+#include "main/glformats.h"
 
 #define FILE_DEBUG_FLAG DEBUG_MIPTREE
 
@@ -318,9 +319,41 @@ void
 brw_miptree_layout(struct brw_context *brw, struct intel_mipmap_tree *mt)
 {
    bool multisampled = mt->num_samples > 1;
-   mt->align_w = intel_horizontal_texture_alignment_unit(brw, mt->format);
-   mt->align_h =
-      intel_vertical_texture_alignment_unit(brw, mt->format, multisampled);
+   bool gen6_hiz_or_stencil = false;
+
+   if (brw->gen == 6 && mt->non_mip_arrays) {
+      GLenum base_format = _mesa_get_format_base_format(mt->format);
+      gen6_hiz_or_stencil = _mesa_is_depth_or_stencil_format(base_format);
+   }
+
+   if (gen6_hiz_or_stencil) {
+      /* On gen6, we use non_mip_arrays for stencil/hiz because the hardware
+       * doesn't support multiple mip levels on stencil/hiz.
+       *
+       * PRM Vol 2, Part 1, 7.5.3 Hierarchical Depth Buffer:
+       * "The hierarchical depth buffer does not support the LOD field"
+       *
+       * PRM Vol 2, Part 1, 7.5.4.1 Separate Stencil Buffer:
+       * "The stencil depth buffer does not support the LOD field"
+       */
+      if (mt->format == MESA_FORMAT_S_UINT8) {
+         /* Stencil uses W tiling, so we force W tiling alignment for the
+          * non_mip_arrays based mip-levels.
+          */
+         mt->align_w = 64;
+         mt->align_h = 64;
+      } else {
+         /* Depth uses Y tiling, so we force need Y tiling alignment for the
+          * non_mip_arrays based mip-levels.
+          */
+         mt->align_w = 128 / mt->cpp;
+         mt->align_h = 32;
+      }
+   } else {
+      mt->align_w = intel_horizontal_texture_alignment_unit(brw, mt->format);
+      mt->align_h =
+         intel_vertical_texture_alignment_unit(brw, mt->format, multisampled);
+   }
 
    switch (mt->target) {
    case GL_TEXTURE_CUBE_MAP:
-- 
2.0.1