diff --git a/src/gallium/auxiliary/tgsi/tgsi_from_mesa.c b/src/gallium/auxiliary/tgsi/tgsi_from_mesa.c
index 659156b5190..19384cf4b27 100644
--- a/src/gallium/auxiliary/tgsi/tgsi_from_mesa.c
+++ b/src/gallium/auxiliary/tgsi/tgsi_from_mesa.c
@@ -123,6 +123,10 @@ tgsi_get_gl_varying_semantic(gl_varying_slot attr,
       *semantic_name = TGSI_SEMANTIC_VIEWPORT_INDEX;
       *semantic_index = 0;
       break;
+   case VARYING_SLOT_FACE:
+      *semantic_name = TGSI_SEMANTIC_FACE;
+      *semantic_index = 0;
+      break;
    case VARYING_SLOT_PNTC:
       *semantic_name = TGSI_SEMANTIC_PCOORD;
       *semantic_index = 0;