diff --git a/src/nouveau/winsys/nouveau_device.c b/src/nouveau/winsys/nouveau_device.c
index 49284b6c768..14f6a5f84cb 100644
--- a/src/nouveau/winsys/nouveau_device.c
+++ b/src/nouveau/winsys/nouveau_device.c
@@ -109,6 +109,8 @@ max_warps_per_mp_for_sm(uint8_t sm)
       return 64;
    default:
       assert(!"unkown SM version");
+      // return the biggest known value
+      return 64;
    }
 }