From b7f16e21e77986953a79d71f0e6758dbda49be64 Mon Sep 17 00:00:00 2001
From: Robert Moore <Robert.Moore@intel.com>
Date: Fri, 4 Dec 2009 09:22:56 -0800
Subject: [PATCH] Fix mutex errors when running _REG methods.

Fixes a problem where mutex errors can occur when running a _REG method
that is in the same scope as a method-defined operation region or an
operation region under a module-level IF block. This is rare, so the
problem has not been seen before. ACPICA BZ 826. Lin Ming, Bob Moore.
---
 source/components/dispatcher/dswload.c | 35 +++++++++++++++-----------
 1 file changed, 21 insertions(+), 14 deletions(-)

diff --git a/source/components/dispatcher/dswload.c b/source/components/dispatcher/dswload.c
index 47b3e6628..48c4ae6f1 100644
--- a/source/components/dispatcher/dswload.c
+++ b/source/components/dispatcher/dswload.c
@@ -1158,33 +1158,40 @@ AcpiDsLoad2EndOp (
             }
 
             /*
-             * If we are executing a method, initialize the region
+             * The OpRegion is not fully parsed at this time. The only valid
+             * argument is the SpaceId. (We must save the address of the
+             * AML of the address and length operands)
+             *
+             * If we have a valid region, initialize it. The namespace is
+             * unlocked at this point.
+             *
+             * Need to unlock interpreter if it is locked (if we are running
+             * a control method), in order to allow _REG methods to be run
+             * during AcpiEvInitializeRegion.
              */
             if (WalkState->MethodNode)
             {
+                /*
+                 * Executing a method: initialize the region and unlock
+                 * the interpreter
+                 */
                 Status = AcpiExCreateRegion (Op->Named.Data, Op->Named.Length,
                             RegionSpace, WalkState);
                 if (ACPI_FAILURE (Status))
                 {
                     return (Status);
                 }
+
+                AcpiExExitInterpreter ();
             }
 
-            /*
-             * The OpRegion is not fully parsed at this time. Only valid
-             * argument is the SpaceId. (We must save the address of the
-             * AML of the address and length operands)
-             */
-
-            /*
-             * If we have a valid region, initialize it
-             * Namespace is NOT locked at this point.
-             *
-             * TBD: need to unlock interpreter if it is locked, in order
-             * to allow _REG methods to be run.
-             */
             Status = AcpiEvInitializeRegion (AcpiNsGetAttachedObject (Node),
                         FALSE);
+            if (WalkState->MethodNode)
+            {
+                AcpiExEnterInterpreter ();
+            }
+
             if (ACPI_FAILURE (Status))
             {
                 /*