From 7a4b8131ac7b47feb110b3e0142d4207ee79a025 Mon Sep 17 00:00:00 2001
From: Lin Ming <ming.m.lin@intel.com>
Date: Thu, 13 Nov 2008 11:25:22 +0800
Subject: [PATCH] ACPICA: Enhance implicit return mechanism

For Windows compatibility, return an implicit integer of value
zero for methods that have no executable code. A default implicit
value of zero is provided for methods. Lin Ming.

Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
---
 drivers/acpi/parser/psxface.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/drivers/acpi/parser/psxface.c b/drivers/acpi/parser/psxface.c
index 4985ce58c024..41b0c8c052a8 100644
--- a/drivers/acpi/parser/psxface.c
+++ b/drivers/acpi/parser/psxface.c
@@ -295,6 +295,22 @@ acpi_status acpi_ps_execute_method(struct acpi_evaluate_info *info)
 		goto cleanup;
 	}
 
+	/*
+	 * Start method evaluation with an implicit return of zero.
+	 * This is done for Windows compatibility.
+	 */
+	if (acpi_gbl_enable_interpreter_slack) {
+		walk_state->implicit_return_obj =
+		    acpi_ut_create_internal_object(ACPI_TYPE_INTEGER);
+		if (!walk_state->implicit_return_obj) {
+			status = AE_NO_MEMORY;
+			acpi_ds_delete_walk_state(walk_state);
+			goto cleanup;
+		}
+
+		walk_state->implicit_return_obj->integer.value = 0;
+	}
+
 	/* Parse the AML */
 
 	status = acpi_ps_parse_aml(walk_state);
-- 
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