i965: Use the separate stencil buffer's offsets for stencil setup.

For a packed depth/stencil buffer on separate stencil hardware, the
separate depth miptree is set up with alignment of 4,4 and the separate
stencil miptree is setup with alignment of 8,8.  We can't just use the
irb->draw_{x,y} offsets for stencil, since that is the offset in the
depth miptree.

Fixes 12 piglit depthstencil testcases on ivb.

Acked-by: Chad Versace <chad.versace@linux.intel.com>

src/mesa/drivers/dri/i965/brw_misc_state.c

@@ -317,6 +317,16 @@ brw_get_depthstencil_tile_masks(struct intel_mipmap_tree *depth_mt,
    *out_tile_mask_y = tile_mask_y;
 }
 
+static struct intel_mipmap_tree *
+get_stencil_miptree(struct intel_renderbuffer *irb)
+{
+   if (!irb)
+      return NULL;
+   if (irb->mt->stencil_mt)
+      return irb->mt->stencil_mt;
+   return irb->mt;
+}
+
 void
 brw_workaround_depthstencil_alignment(struct brw_context *brw)
 {
@@ -328,13 +338,12 @@ brw_workaround_depthstencil_alignment(struct brw_context *brw)
    struct intel_renderbuffer *depth_irb = intel_get_renderbuffer(fb, BUFFER_DEPTH);
    struct intel_renderbuffer *stencil_irb = intel_get_renderbuffer(fb, BUFFER_STENCIL);
    struct intel_mipmap_tree *depth_mt = NULL;
-   struct intel_mipmap_tree *stencil_mt = NULL;
+   struct intel_mipmap_tree *stencil_mt = get_stencil_miptree(stencil_irb);
    uint32_t tile_x = 0, tile_y = 0, stencil_tile_x = 0, stencil_tile_y = 0;
+   uint32_t stencil_draw_x = 0, stencil_draw_y = 0;
 
    if (depth_irb)
       depth_mt = depth_irb->mt;
-   if (stencil_irb)
-      stencil_mt = stencil_irb->mt;
 
    uint32_t tile_mask_x, tile_mask_y;
    brw_get_depthstencil_tile_masks(depth_mt, stencil_mt,
@@ -372,13 +381,20 @@ brw_workaround_depthstencil_alignment(struct brw_context *brw)
             intel_renderbuffer_set_draw_offset(stencil_irb);
          }
 
+         stencil_mt = get_stencil_miptree(stencil_irb);
+
          tile_x = depth_irb->draw_x & tile_mask_x;
          tile_y = depth_irb->draw_y & tile_mask_y;
       }
 
       if (stencil_irb) {
-         int stencil_tile_x = stencil_irb->draw_x & tile_mask_x;
-         int stencil_tile_y = stencil_irb->draw_y & tile_mask_y;
+         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
@@ -394,8 +410,12 @@ brw_workaround_depthstencil_alignment(struct brw_context *brw)
 
    /* If we have (just) stencil, check it for ignored low bits as well */
    if (stencil_irb) {
-      stencil_tile_x = stencil_irb->draw_x & tile_mask_x;
-      stencil_tile_y = stencil_irb->draw_y & tile_mask_y;
+      intel_miptree_get_image_offset(stencil_mt,
+                                     stencil_irb->mt_level,
+                                     stencil_irb->mt_layer,
+                                     &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 (stencil_tile_x & 7 || stencil_tile_y & 7)
          rebase_stencil = true;
@@ -408,11 +428,16 @@ brw_workaround_depthstencil_alignment(struct brw_context *brw)
 
    if (rebase_stencil) {
       intel_renderbuffer_move_to_temp(intel, stencil_irb);
+      stencil_mt = get_stencil_miptree(stencil_irb);
 
-      stencil_tile_x = stencil_irb->draw_x & tile_mask_x;
-      stencil_tile_y = stencil_irb->draw_y & tile_mask_y;
+      intel_miptree_get_image_offset(stencil_mt,
+                                     stencil_irb->mt_level,
+                                     stencil_irb->mt_layer,
+                                     &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_mt) {
+      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) {
@@ -484,9 +509,7 @@ brw_workaround_depthstencil_alignment(struct brw_context *brw)
       }
    }
    if (stencil_irb) {
-      stencil_mt = stencil_irb->mt;
-      if (stencil_mt->stencil_mt)
-         stencil_mt = stencil_mt->stencil_mt;
+      stencil_mt = get_stencil_miptree(stencil_irb);
 
       brw->depthstencil.stencil_mt = stencil_mt;
       if (stencil_mt->format == MESA_FORMAT_S8) {
@@ -495,8 +518,8 @@ brw_workaround_depthstencil_alignment(struct brw_context *brw)
           * that the region is untiled even though it's W tiled.
           */
          brw->depthstencil.stencil_offset =
-            (stencil_irb->draw_y & ~tile_mask_y) * stencil_mt->region->pitch +
-            (stencil_irb->draw_x & ~tile_mask_x) * 64;
+            (stencil_draw_y & ~tile_mask_y) * stencil_mt->region->pitch +
+            (stencil_draw_x & ~tile_mask_x) * 64;
       }
    }
 }