diff --git a/include/acpi/acpixf.h b/include/acpi/acpixf.h
index 3d7ab9e..9512f04 100644
--- a/include/acpi/acpixf.h
+++ b/include/acpi/acpixf.h
@@ -314,6 +314,8 @@
  */
 acpi_status acpi_get_register(u32 register_id, u32 * return_value);
 
+acpi_status acpi_get_register_unlocked(u32 register_id, u32 *return_value);
+
 acpi_status acpi_set_register(u32 register_id, u32 value);
 
 acpi_status