diff --git a/src/mainboard/lenovo/t420/dsdt.asl b/src/mainboard/lenovo/t420/dsdt.asl
index f0964d3561..b83fe38daa 100644
--- a/src/mainboard/lenovo/t420/dsdt.asl
+++ b/src/mainboard/lenovo/t420/dsdt.asl
@@ -35,4 +35,5 @@ DefinitionBlock(
 	}
 
 	#include <southbridge/intel/common/acpi/sleepstates.asl>
+	#include <ec/lenovo/h8/acpi/thinklight.asl>
 }