3 files changed, 23 insertions, 14 deletions
diff --git a/src/mesa/drivers/dri/i965/brw_context.h b/src/mesa/drivers/dri/i965/brw_context.h
index c1787a8cf7f..0e7bd21b019 100644
--- a/src/mesa/drivers/dri/i965/brw_context.h
+++ b/src/mesa/drivers/dri/i965/brw_context.h
@@ -1601,7 +1601,27 @@ gl_clip_plane *brw_select_clip_planes(struct gl_context *ctx);
 /* brw_draw_upload.c */
 unsigned brw_get_vertex_surface_type(struct brw_context *brw,
                                      const struct gl_client_array *glarray);
-unsigned brw_get_index_type(GLenum type);
+
+static inline unsigned
+brw_get_index_type(GLenum type)
+{
+   assert((type == GL_UNSIGNED_BYTE)
+          || (type == GL_UNSIGNED_SHORT)
+          || (type == GL_UNSIGNED_INT));
+
+   /* The possible values for type are GL_UNSIGNED_BYTE (0x1401),
+    * GL_UNSIGNED_SHORT (0x1403), and GL_UNSIGNED_INT (0x1405) which we want
+    * to map to scale factors of 0, 1, and 2, respectively.  These scale
+    * factors are then left-shfited by 8 to be in the correct position in the
+    * CMD_INDEX_BUFFER packet.
+    *
+    * Subtracting 0x1401 gives 0, 2, and 4.  Shifting left by 7 afterwards
+    * gives 0x00000000, 0x00000100, and 0x00000200.  These just happen to be
+    * the values the need to be written in the CMD_INDEX_BUFFER packet.
+    */
+   return (type - 0x1401) << 7;
+}
+
 void brw_prepare_vertices(struct brw_context *brw);
 
 /* brw_wm_surface_state.c */
diff --git a/src/mesa/drivers/dri/i965/brw_draw_upload.c b/src/mesa/drivers/dri/i965/brw_draw_upload.c
index 8123da8377c..52dcb6f2c4c 100644
--- a/src/mesa/drivers/dri/i965/brw_draw_upload.c
+++ b/src/mesa/drivers/dri/i965/brw_draw_upload.c
@@ -344,17 +344,6 @@ brw_get_vertex_surface_type(struct brw_context *brw,
    }
 }
 
-unsigned
-brw_get_index_type(GLenum type)
-{
-   switch (type) {
-   case GL_UNSIGNED_BYTE:  return BRW_INDEX_BYTE;
-   case GL_UNSIGNED_SHORT: return BRW_INDEX_WORD;
-   case GL_UNSIGNED_INT:   return BRW_INDEX_DWORD;
-   default: unreachable("not reached");
-   }
-}
-
 static void
 copy_array_to_vbo_array(struct brw_context *brw,
 			struct brw_vertex_element *element,
@@ -963,7 +952,7 @@ static void brw_emit_index_buffer(struct brw_context *brw)
    BEGIN_BATCH(3);
    OUT_BATCH(CMD_INDEX_BUFFER << 16 |
              cut_index_setting |
-             brw_get_index_type(index_buffer->type) << 8 |
+             brw_get_index_type(index_buffer->type) |
              1);
    OUT_RELOC(brw->ib.bo,
              I915_GEM_DOMAIN_VERTEX, 0,
diff --git a/src/mesa/drivers/dri/i965/gen8_draw_upload.c b/src/mesa/drivers/dri/i965/gen8_draw_upload.c
index 0d6feec8ab0..1af90ecc6a4 100644
--- a/src/mesa/drivers/dri/i965/gen8_draw_upload.c
+++ b/src/mesa/drivers/dri/i965/gen8_draw_upload.c
@@ -251,7 +251,7 @@ gen8_emit_index_buffer(struct brw_context *brw)
 
    BEGIN_BATCH(5);
    OUT_BATCH(CMD_INDEX_BUFFER << 16 | (5 - 2));
-   OUT_BATCH(brw_get_index_type(index_buffer->type) << 8 | mocs_wb);
+   OUT_BATCH(brw_get_index_type(index_buffer->type) | mocs_wb);
    OUT_RELOC64(brw->ib.bo, I915_GEM_DOMAIN_VERTEX, 0, 0);
    OUT_BATCH(brw->ib.bo->size);
    ADVANCE_BATCH();