diff --git a/src/vulkan/anv_x11.c b/src/vulkan/anv_x11.c
index cc11a5fc762..aee5775c9de 100644
--- a/src/vulkan/anv_x11.c
+++ b/src/vulkan/anv_x11.c
@@ -143,6 +143,8 @@ VkResult anv_CreateSwapChainWSI(
          &image_h);
 
       image = anv_image_from_handle(image_h);
+      assert(anv_format_is_color(image->format));
+
       surface = &image->primary_surface;
 
       anv_AllocMemory(_device,