intel: Add map_stencil_as_y_tiled to intel_region_get_aligned_offset.

This patch modifies intel_region_get_aligned_offset() to make the
appropriate calculation when the blorp engine sets up a W-tiled
stencil buffer using a Y-tiled SURFACE_STATE.

NOTE: This is a candidate for stable release branches.

Acked-by: Eric Anholt <eric@anholt.net>
diff --git a/src/mesa/drivers/dri/i965/brw_blorp.cpp b/src/mesa/drivers/dri/i965/brw_blorp.cpp
index 7e45191..fa7fee7 100644
--- a/src/mesa/drivers/dri/i965/brw_blorp.cpp
+++ b/src/mesa/drivers/dri/i965/brw_blorp.cpp
@@ -129,7 +129,8 @@
    *tile_y = y_offset & mask_y;
 
    return intel_region_get_aligned_offset(region, x_offset & ~mask_x,
-                                          y_offset & ~mask_y);
+                                          y_offset & ~mask_y,
+                                          map_stencil_as_y_tiled);
 }
 
 
diff --git a/src/mesa/drivers/dri/i965/brw_misc_state.c b/src/mesa/drivers/dri/i965/brw_misc_state.c
index 52926fb..6dfa08e 100644
--- a/src/mesa/drivers/dri/i965/brw_misc_state.c
+++ b/src/mesa/drivers/dri/i965/brw_misc_state.c
@@ -474,7 +474,7 @@
 
       offset = intel_region_get_aligned_offset(region,
                                                draw_x & ~tile_mask_x,
-                                               draw_y & ~tile_mask_y);
+                                               draw_y & ~tile_mask_y, false);
 
       BEGIN_BATCH(len);
       OUT_BATCH(_3DSTATE_DEPTH_BUFFER << 16 | (len - 2));
@@ -518,7 +518,8 @@
          uint32_t hiz_offset =
             intel_region_get_aligned_offset(hiz_region,
                                             draw_x & ~tile_mask_x,
-                                            (draw_y & ~tile_mask_y) / 2);
+                                            (draw_y & ~tile_mask_y) / 2,
+                                            false);
 
 	 BEGIN_BATCH(3);
 	 OUT_BATCH((_3DSTATE_HIER_DEPTH_BUFFER << 16) | (3 - 2));
diff --git a/src/mesa/drivers/dri/i965/gen6_blorp.cpp b/src/mesa/drivers/dri/i965/gen6_blorp.cpp
index 3e0b80e..1f536bf 100644
--- a/src/mesa/drivers/dri/i965/gen6_blorp.cpp
+++ b/src/mesa/drivers/dri/i965/gen6_blorp.cpp
@@ -843,7 +843,7 @@
       uint32_t offset =
          intel_region_get_aligned_offset(params->depth.mt->region,
                                          draw_x & ~tile_mask_x,
-                                         draw_y & ~tile_mask_y);
+                                         draw_y & ~tile_mask_y, false);
 
       /* According to the Sandy Bridge PRM, volume 2 part 1, pp326-327
        * (3DSTATE_DEPTH_BUFFER dw5), in the documentation for "Depth
@@ -896,7 +896,7 @@
       uint32_t hiz_offset =
          intel_region_get_aligned_offset(hiz_region,
                                          draw_x & ~tile_mask_x,
-                                         (draw_y & ~tile_mask_y) / 2);
+                                         (draw_y & ~tile_mask_y) / 2, false);
 
       BEGIN_BATCH(3);
       OUT_BATCH((_3DSTATE_HIER_DEPTH_BUFFER << 16) | (3 - 2));
diff --git a/src/mesa/drivers/dri/i965/gen7_blorp.cpp b/src/mesa/drivers/dri/i965/gen7_blorp.cpp
index 00f13a5..eeeeabe 100644
--- a/src/mesa/drivers/dri/i965/gen7_blorp.cpp
+++ b/src/mesa/drivers/dri/i965/gen7_blorp.cpp
@@ -591,7 +591,7 @@
       uint32_t offset =
          intel_region_get_aligned_offset(params->depth.mt->region,
                                          draw_x & ~tile_mask_x,
-                                         draw_y & ~tile_mask_y);
+                                         draw_y & ~tile_mask_y, false);
 
       /* According to the Sandy Bridge PRM, volume 2 part 1, pp326-327
        * (3DSTATE_DEPTH_BUFFER dw5), in the documentation for "Depth
@@ -640,7 +640,7 @@
       uint32_t hiz_offset =
          intel_region_get_aligned_offset(hiz_region,
                                          draw_x & ~tile_mask_x,
-                                         (draw_y & ~tile_mask_y) / 2);
+                                         (draw_y & ~tile_mask_y) / 2, false);
 
       BEGIN_BATCH(3);
       OUT_BATCH((GEN7_3DSTATE_HIER_DEPTH_BUFFER << 16) | (3 - 2));
diff --git a/src/mesa/drivers/dri/i965/gen7_misc_state.c b/src/mesa/drivers/dri/i965/gen7_misc_state.c
index 9709b8e..1d22448 100644
--- a/src/mesa/drivers/dri/i965/gen7_misc_state.c
+++ b/src/mesa/drivers/dri/i965/gen7_misc_state.c
@@ -181,7 +181,8 @@
 
       offset = intel_region_get_aligned_offset(region,
                                                draw_x & ~tile_mask_x,
-                                               draw_y & ~tile_mask_y);
+                                               draw_y & ~tile_mask_y,
+                                               false);
 
       assert(region->tiling == I915_TILING_Y);
 
@@ -215,7 +216,8 @@
       uint32_t hiz_offset =
          intel_region_get_aligned_offset(hiz_mt->region,
                                          draw_x & ~tile_mask_x,
-                                         (draw_y & ~tile_mask_y) / 2);
+                                         (draw_y & ~tile_mask_y) / 2,
+                                         false);
       BEGIN_BATCH(3);
       OUT_BATCH(GEN7_3DSTATE_HIER_DEPTH_BUFFER << 16 | (3 - 2));
       OUT_BATCH(hiz_mt->region->pitch * hiz_mt->region->cpp - 1);
diff --git a/src/mesa/drivers/dri/intel/intel_fbo.c b/src/mesa/drivers/dri/intel/intel_fbo.c
index bd9548b..ba360c5 100644
--- a/src/mesa/drivers/dri/intel/intel_fbo.c
+++ b/src/mesa/drivers/dri/intel/intel_fbo.c
@@ -586,7 +586,7 @@
    *tile_x = irb->draw_x & mask_x;
    *tile_y = irb->draw_y & mask_y;
    return intel_region_get_aligned_offset(region, irb->draw_x & ~mask_x,
-                                          irb->draw_y & ~mask_y);
+                                          irb->draw_y & ~mask_y, false);
 }
 
 /**
diff --git a/src/mesa/drivers/dri/intel/intel_regions.c b/src/mesa/drivers/dri/intel/intel_regions.c
index 18402d6..7cb008c 100644
--- a/src/mesa/drivers/dri/intel/intel_regions.c
+++ b/src/mesa/drivers/dri/intel/intel_regions.c
@@ -437,12 +437,26 @@
  */
 uint32_t
 intel_region_get_aligned_offset(struct intel_region *region, uint32_t x,
-                                uint32_t y)
+                                uint32_t y, bool map_stencil_as_y_tiled)
 {
    int cpp = region->cpp;
    uint32_t pitch = region->pitch * cpp;
+   uint32_t tiling = region->tiling;
 
-   switch (region->tiling) {
+   if (map_stencil_as_y_tiled) {
+      tiling = I915_TILING_Y;
+
+      /* When mapping a W-tiled stencil buffer as Y-tiled, each 64-high W-tile
+       * gets transformed into a 32-high Y-tile.  Accordingly, the pitch of
+       * the resulting region is twice the pitch of the original region, since
+       * each row in the Y-tiled view corresponds to two rows in the actual
+       * W-tiled surface.  So we need to correct the pitch before computing
+       * the offsets.
+       */
+      pitch *= 2;
+   }
+
+   switch (tiling) {
    default:
       assert(false);
    case I915_TILING_NONE:
diff --git a/src/mesa/drivers/dri/intel/intel_regions.h b/src/mesa/drivers/dri/intel/intel_regions.h
index e259a1e..8737a6d 100644
--- a/src/mesa/drivers/dri/intel/intel_regions.h
+++ b/src/mesa/drivers/dri/intel/intel_regions.h
@@ -140,7 +140,7 @@
 
 uint32_t
 intel_region_get_aligned_offset(struct intel_region *region, uint32_t x,
-                                uint32_t y);
+                                uint32_t y, bool map_stencil_as_y_tiled);
 
 /**
  * Used with images created with image_from_names