diff --git a/kms++/src/helpers.h b/kms++/src/helpers.h
--- /dev/null
+++ b/kms++/src/helpers.h
@@ -0,0 +1,12 @@
+#pragma once
+
+#include <xf86drm.h>
+#include <xf86drmMode.h>
+
+namespace kms
+{
+struct Videomode;
+
+Videomode drm_mode_to_video_mode(const drmModeModeInfo& drmmode);
+drmModeModeInfo video_mode_to_drm_mode(const Videomode& mode);
+}