diff --git a/tests/modetest/modetest.c b/tests/modetest/modetest.c
index 35045c87..f65a033b 100644
--- a/tests/modetest/modetest.c
+++ b/tests/modetest/modetest.c
@@ -568,7 +568,8 @@ set_mode(struct connector *c, int count, int page_flip)
 	kms_bo_get_prop(bo, KMS_HANDLE, &handle);
 	ret = drmModeAddFB(fd, width, height, 24, 32, stride, handle, &fb_id);
 	if (ret) {
-		fprintf(stderr, "failed to add fb: %s\n", strerror(errno));
+		fprintf(stderr, "failed to add fb (%ux%u): %s\n",
+			width, height, strerror(errno));
 		return;
 	}