diff --git a/drivers/acpi/acpica/acinterp.h b/drivers/acpi/acpica/acinterp.h
index 3731e1c..4ee9058 100644
--- a/drivers/acpi/acpica/acinterp.h
+++ b/drivers/acpi/acpica/acinterp.h
@@ -468,6 +468,8 @@
 
 void acpi_ex_integer_to_string(char *dest, u64 value);
 
+u8 acpi_is_valid_space_id(u8 space_id);
+
 /*
  * exregion - default op_region handlers
  */