ACPICA: Windows compatibility: autoexecute root _INI method

Add support for execution of an _INI method at the namespace root.
Although not defined in the ACPI specification, this support was
added to Windows around the Vista timeframe. It is added here
for Windows compatibility.

Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

drivers/acpi/acpica/nsinit.c

@@ -170,6 +170,21 @@ acpi_status acpi_ns_initialize_devices(void)
 		goto error_exit;
 	}
 
+	/*
+	 * Execute the "global" _INI method that may appear at the root. This
+	 * support is provided for Windows compatibility (Vista+) and is not
+	 * part of the ACPI specification.
+	 */
+	info.evaluate_info->prefix_node = acpi_gbl_root_node;
+	info.evaluate_info->pathname = METHOD_NAME__INI;
+	info.evaluate_info->parameters = NULL;
+	info.evaluate_info->flags = ACPI_IGNORE_RETURN_VALUE;
+
+	status = acpi_ns_evaluate(info.evaluate_info);
+	if (ACPI_SUCCESS(status)) {
+		info.num_INI++;
+	}
+
 	/* Walk namespace to execute all _INIs on present devices */
 
 	status = acpi_ns_walk_namespace(ACPI_TYPE_ANY, ACPI_ROOT_OBJECT,