diff --git a/drivers/acpi/processor_perflib.c b/drivers/acpi/processor_perflib.c
index 60e543d..11088cf 100644
--- a/drivers/acpi/processor_perflib.c
+++ b/drivers/acpi/processor_perflib.c
@@ -39,6 +39,8 @@
 #include <acpi/acpi_drivers.h>
 #include <acpi/processor.h>
 
+#define PREFIX "ACPI: "
+
 #define ACPI_PROCESSOR_CLASS		"processor"
 #define ACPI_PROCESSOR_FILE_PERFORMANCE	"performance"
 #define _COMPONENT		ACPI_PROCESSOR_COMPONENT