diff --git a/src/gpu/GrContextThreadSafeProxy.cpp b/src/gpu/GrContextThreadSafeProxy.cpp
index 8da3afe..8bf5afb 100644
--- a/src/gpu/GrContextThreadSafeProxy.cpp
+++ b/src/gpu/GrContextThreadSafeProxy.cpp
@@ -38,6 +38,8 @@
         return SkSurfaceCharacterization(); // return an invalid characterization
     }
 
+    SkASSERT(isTextureable || !isMipMapped);
+
     if (GrBackendApi::kOpenGL != backendFormat.backend() && willUseGLFBO0) {
         // The willUseGLFBO0 flags can only be used for a GL backend.
         return SkSurfaceCharacterization(); // return an invalid characterization