diff --git a/drivers/acpi/internal.h b/drivers/acpi/internal.h
index 4a35f6e..44b8402 100644
--- a/drivers/acpi/internal.h
+++ b/drivers/acpi/internal.h
@@ -3,6 +3,12 @@
 int acpi_scan_init(void);
 int acpi_system_init(void);
 
+#ifdef CONFIG_ACPI_DEBUG
+int acpi_debug_init(void);
+#else
+static inline int acpi_debug_init(void) { return 0; }
+#endif
+
 /* --------------------------------------------------------------------------
                                   Power Resource
    -------------------------------------------------------------------------- */