diff --git a/sys/dev/drm/i915/intel_opregion.c b/sys/dev/drm/i915/intel_opregion.c
--- a/sys/dev/drm/i915/intel_opregion.c
+++ b/sys/dev/drm/i915/intel_opregion.c
@@ -829,7 +829,9 @@
 	}
 
 	/* just clear all opregion memory pointers now */
-	iounmap(opregion->header);
+	if (opregion->header)
+		iounmap(opregion->header);
+	opregion->header = NULL;
 	if (opregion->rvda) {
 		iounmap(opregion->rvda);
 		opregion->rvda = NULL;