[Mesa-dev] [PATCH] isl: Add assertions for render target swizzle restrictions

[Jason Ekstrand]

---
 src/intel/isl/isl_surface_state.c | 32 ++++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/src/intel/isl/isl_surface_state.c b/src/intel/isl/isl_surface_state.c
index b735478..c7b220b 100644
--- a/src/intel/isl/isl_surface_state.c
+++ b/src/intel/isl/isl_surface_state.c
@@ -453,6 +453,38 @@ isl_genX(surf_fill_state_s)(const struct isl_device *dev, void *state,
 #endif
 
 #if (GEN_GEN >= 8 || GEN_IS_HASWELL)
+   if (info->view->usage & ISL_SURF_USAGE_RENDER_TARGET_BIT) {
+      /* From the Sky Lake PRM Vol. 2d,
+       * RENDER_SURFACE_STATE::Shader Channel Select Red
+       *
+       *    "For Render Target, Red, Green and Blue Shader Channel Selects
+       *    MUST be such that only valid components can be swapped i.e. only
+       *    change the order of components in the pixel. Any other values for
+       *    these Shader Channel Select fields are not valid for Render
+       *    Targets. This also means that there MUST not be multiple shader
+       *    channels mapped to the same RT channel."
+       */
+      assert(info->view->swizzle.r == ISL_CHANNEL_SELECT_RED ||
+             info->view->swizzle.r == ISL_CHANNEL_SELECT_GREEN ||
+             info->view->swizzle.r == ISL_CHANNEL_SELECT_BLUE);
+      assert(info->view->swizzle.g == ISL_CHANNEL_SELECT_RED ||
+             info->view->swizzle.g == ISL_CHANNEL_SELECT_GREEN ||
+             info->view->swizzle.g == ISL_CHANNEL_SELECT_BLUE);
+      assert(info->view->swizzle.b == ISL_CHANNEL_SELECT_RED ||
+             info->view->swizzle.b == ISL_CHANNEL_SELECT_GREEN ||
+             info->view->swizzle.b == ISL_CHANNEL_SELECT_BLUE);
+      assert(info->view->swizzle.r != info->view->swizzle.g);
+      assert(info->view->swizzle.r != info->view->swizzle.b);
+      assert(info->view->swizzle.g != info->view->swizzle.b);
+
+      /* From the Sky Lake PRM Vol. 2d,
+       * RENDER_SURFACE_STATE::Shader Channel Select Alpha
+       *
+       *    "For Render Target, this field MUST be programmed to
+       *    value = SCS_ALPHA."
+       */
+      assert(info->view->swizzle.a == ISL_CHANNEL_SELECT_ALPHA);
+   }
    s.ShaderChannelSelectRed = info->view->swizzle.r;
    s.ShaderChannelSelectGreen = info->view->swizzle.g;
    s.ShaderChannelSelectBlue = info->view->swizzle.b;
-- 
2.5.0.400.gff86faf