From 3512efa9b2b63b3bec6277cf4c878eb7e54f92ef Mon Sep 17 00:00:00 2001
From: li-elvin <li-elvin@6f19259b-4bc3-4df7-8a09-765794883524>
Date: Tue, 15 Nov 2011 07:59:21 +0000
Subject: [PATCH] CSM is updated to remove RaiseTPL (TPL_HIGH_LEVEL) and
 disable 2 known UEFI interrupts instead. This is needed to process HPET timer
 interrupt before going into real mode.

Signed-off-by: li-elvin
Reviewed-by: vanjeff

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@12701 6f19259b-4bc3-4df7-8a09-765794883524
---
 .../Csm/LegacyBiosDxe/LegacyBootSupport.c             | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/IntelFrameworkModulePkg/Csm/LegacyBiosDxe/LegacyBootSupport.c b/IntelFrameworkModulePkg/Csm/LegacyBiosDxe/LegacyBootSupport.c
index 397295bcf1..04013d9708 100644
--- a/IntelFrameworkModulePkg/Csm/LegacyBiosDxe/LegacyBootSupport.c
+++ b/IntelFrameworkModulePkg/Csm/LegacyBiosDxe/LegacyBootSupport.c
@@ -1204,10 +1204,17 @@ GenericLegacyBoot (
     //
     EfiSignalEventLegacyBoot ();
     DEBUG ((EFI_D_INFO, "Legacy INT19 Boot...\n"));
+
+    //
+    // Disable DXE Timer while executing in real mode
     //
-    // Raise TPL to high level to disable CPU interrupts
+    Private->Timer->SetTimerPeriod (Private->Timer, 0);
+    
     //
-    gBS->RaiseTPL (TPL_HIGH_LEVEL);
+    // Save and disable interrupt of debug timer
+    //
+    SaveAndSetDebugTimerInterrupt (FALSE);
+
 
     //
     // Put the 8259 into its legacy mode by reprogramming the vector bases
-- 
2.39.2