[Mesa-dev] [PATCH v2] i965/skl: Fix the order of the arguments for the LD sampler message

[Neil Roberts]

In Skylake the order of the arguments for sample messages with the LD
type are u, v, lod, r whereas previously they were u, lod, v, r.

This fixes 144 Piglit tests including ones that directly use
texelFetch and also some using the meta stencil blit path which
appears to use texelFetch in its shader.

v2: Fix sampling 1D textures
---

I realised that v1 of the patch would end up putting the lod in the
wrong argument for 1D textures so here is a v2. This time I have run
it through a full Piglit run and it doesn't cause any regressions.

 src/mesa/drivers/dri/i965/brw_fs_visitor.cpp | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp b/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp
index 6b48f70..287ee47 100644
--- a/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp
@@ -1742,15 +1742,26 @@ fs_visitor::emit_texture_gen7(ir_texture_opcode op, fs_reg dst,
       length++;
       break;
    case ir_txf:
-      /* Unfortunately, the parameters for LD are intermixed: u, lod, v, r. */
+      /* Unfortunately, the parameters for LD are intermixed: u, lod, v, r.
+       * On Gen9 they are u, v, lod, r
+       */
+
       emit(MOV(retype(sources[length], BRW_REGISTER_TYPE_D), coordinate));
       coordinate = offset(coordinate, 1);
       length++;
 
+      if (brw->gen >= 9) {
+         if (coord_components >= 2) {
+            emit(MOV(retype(sources[length], BRW_REGISTER_TYPE_D), coordinate));
+            coordinate = offset(coordinate, 1);
+         }
+         length++;
+      }
+
       emit(MOV(retype(sources[length], BRW_REGISTER_TYPE_D), lod));
       length++;
 
-      for (int i = 1; i < coord_components; i++) {
+      for (int i = brw->gen >= 9 ? 2 : 1; i < coord_components; i++) {
 	 emit(MOV(retype(sources[length], BRW_REGISTER_TYPE_D), coordinate));
 	 coordinate = offset(coordinate, 1);
 	 length++;
-- 
1.9.3