[Mesa-dev] [PATCH 3/6] i965/skl: Fix the qpitch value

[Neil Roberts]

On Skylake the qpitch value is uploaded as part of the surface state
so we don't need to add the extra rows that are done for other
generations. However for 3D textures it needs to be aligned to the
tile height. Unlike previous generations the qpitch is measured as a
multiple of the block size for compressed surfaces. When the
horizontal mipmap layout is used for 1D textures then the qpitch is
measured in pixels instead of rows.
---
 src/mesa/drivers/dri/i965/brw_tex_layout.c    | 44 +++++++++++++++++++++------
 src/mesa/drivers/dri/i965/intel_mipmap_tree.h | 10 ++++--
 2 files changed, 41 insertions(+), 13 deletions(-)

diff --git a/src/mesa/drivers/dri/i965/brw_tex_layout.c b/src/mesa/drivers/dri/i965/brw_tex_layout.c
index 851742b..d89a04e 100644
--- a/src/mesa/drivers/dri/i965/brw_tex_layout.c
+++ b/src/mesa/drivers/dri/i965/brw_tex_layout.c
@@ -297,24 +297,48 @@ static void
 brw_miptree_layout_texture_array(struct brw_context *brw,
 				 struct intel_mipmap_tree *mt)
 {
-   int h0, h1;
    unsigned height = mt->physical_height0;
    bool layout_1d = use_linear_1d_layout(brw, mt);
-
-   h0 = ALIGN(mt->physical_height0, mt->align_h);
-   h1 = ALIGN(minify(mt->physical_height0, 1), mt->align_h);
-   if (mt->array_layout == ALL_SLICES_AT_EACH_LOD)
-      mt->qpitch = h0;
-   else
-      mt->qpitch = (h0 + h1 + (brw->gen >= 7 ? 12 : 11) * mt->align_h);
-
-   int physical_qpitch = mt->compressed ? mt->qpitch / 4 : mt->qpitch;
+   int physical_qpitch;
 
    if (layout_1d)
       gen9_miptree_layout_1d(mt);
    else
       brw_miptree_layout_2d(mt);
 
+   if (layout_1d) {
+      physical_qpitch = mt->align_h;
+      /* When using the horizontal layout the qpitch is measured in pixels */
+      mt->qpitch = physical_qpitch * mt->total_width;
+   } else if (brw->gen >= 9) {
+      /* On Gen9 we can pick whatever qpitch we like as long as it's aligned
+       * to the vertical alignment so we don't need to add any extra rows.
+       */
+      mt->qpitch = mt->total_height;
+
+      /* However 3D textures need to be aligned to the tile height. At this
+       * point we don't know which tiling will be used so let's just align it
+       * to 32
+       */
+      if (mt->target == GL_TEXTURE_3D)
+         mt->qpitch = ALIGN(mt->qpitch, 32);
+
+      /* Unlike previous generations the qpitch is now a multiple of the
+       * compressed block size so physical_qpitch matches mt->qpitch.
+       */
+      physical_qpitch = mt->qpitch;
+   } else {
+      int h0 = ALIGN(mt->physical_height0, mt->align_h);
+      int h1 = ALIGN(minify(mt->physical_height0, 1), mt->align_h);
+
+      if (mt->array_layout == ALL_SLICES_AT_EACH_LOD)
+         mt->qpitch = h0;
+      else
+         mt->qpitch = (h0 + h1 + (brw->gen >= 7 ? 12 : 11) * mt->align_h);
+
+      physical_qpitch = mt->compressed ? mt->qpitch / 4 : mt->qpitch;
+   }
+
    for (unsigned level = mt->first_level; level <= mt->last_level; level++) {
       unsigned img_height;
       img_height = ALIGN(height, mt->align_h);
diff --git a/src/mesa/drivers/dri/i965/intel_mipmap_tree.h b/src/mesa/drivers/dri/i965/intel_mipmap_tree.h
index ee9cf1e..247e5b8 100644
--- a/src/mesa/drivers/dri/i965/intel_mipmap_tree.h
+++ b/src/mesa/drivers/dri/i965/intel_mipmap_tree.h
@@ -380,10 +380,14 @@ struct intel_mipmap_tree
    enum miptree_array_layout array_layout;
 
    /**
-    * The distance in rows between array slices in an uncompressed surface.
+    * The distance in between array slices.
     *
-    * For compressed surfaces, slices are stored closer together physically;
-    * the real distance is (qpitch / block height).
+    * The value is the one that is sent in the surface state. The actual
+    * meaning depends on certain criteria. Usually it is simply the number of
+    * uncompressed rows between each slice. However on Gen9+ for compressed
+    * surfaces it is the number of blocks. For 1D surfaces that have the
+    * mipmap tree stored horizontally it is the number of pixels between each
+    * slice.
     */
    uint32_t qpitch;
 
-- 
1.9.3