From: li-elvin <li-elvin@6f19259b-4bc3-4df7-8a09-765794883524>
Date: Mon, 13 Aug 2012 09:33:49 +0000 (+0000)
Subject: Check if active video mode is changed after OpROM starts, if active video mode is... 
X-Git-Tag: edk2-stable201903~13171
X-Git-Url: https://git.proxmox.com/?p=mirror_edk2.git;a=commitdiff_plain;h=edf4af6fb9e62c60cb4b04b3768b1499a807b557

Check if active video mode is changed after OpROM starts, if active video mode is not changed, skip INT10 calls to improve performance.

Signed-off-by: Li Elvin <elvin.li@intel.com>
Reviewed-by: Yao Jiewen<jiewen.yao@intel.com>


git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@13609 6f19259b-4bc3-4df7-8a09-765794883524
---

diff --git a/IntelFrameworkModulePkg/Csm/LegacyBiosDxe/LegacyBiosInterface.h b/IntelFrameworkModulePkg/Csm/LegacyBiosDxe/LegacyBiosInterface.h
index f2e4bbfffd..7e1a6063ef 100644
--- a/IntelFrameworkModulePkg/Csm/LegacyBiosDxe/LegacyBiosInterface.h
+++ b/IntelFrameworkModulePkg/Csm/LegacyBiosDxe/LegacyBiosInterface.h
@@ -132,6 +132,7 @@ WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
 #define LEGACY_PCI_TRACE_00E LEGACY_PCI_TRACE + 0x0E
 #define LEGACY_PCI_TRACE_00F LEGACY_PCI_TRACE + 0x0F
 
+#define BDA_VIDEO_MODE      0x49
 
 typedef struct {
   UINTN   PciSegment;
diff --git a/IntelFrameworkModulePkg/Csm/LegacyBiosDxe/LegacyPci.c b/IntelFrameworkModulePkg/Csm/LegacyBiosDxe/LegacyPci.c
index 45cdd037e6..1d09bb879d 100644
--- a/IntelFrameworkModulePkg/Csm/LegacyBiosDxe/LegacyPci.c
+++ b/IntelFrameworkModulePkg/Csm/LegacyBiosDxe/LegacyPci.c
@@ -2380,7 +2380,7 @@ LegacyBiosInstallRom (
     //
     // Store current mode settings since PrepareToScanRom may change mode.
     //
-    VideoMode = *(UINT8 *) ((UINTN) 0x449);
+    VideoMode = *(UINT8 *) ((UINTN) (0x400 + BDA_VIDEO_MODE));
   }
   //
   // Notify the platform that we are about to scan the ROM
@@ -2520,9 +2520,14 @@ LegacyBiosInstallRom (
     //
     // Set mode settings since PrepareToScanRom may change mode
     //
-    Regs.H.AH = 0x00;
-    Regs.H.AL = VideoMode;
-    Private->LegacyBios.Int86 (&Private->LegacyBios, 0x10, &Regs);
+    if (VideoMode != *(UINT8 *) ((UINTN) (0x400 + BDA_VIDEO_MODE))) {
+      //
+      // The active video mode is changed, restore it to original mode.
+      //
+      Regs.H.AH = 0x00;
+      Regs.H.AL = VideoMode;
+      Private->LegacyBios.Int86 (&Private->LegacyBios, 0x10, &Regs);
+    }
   }
   //
   // Regs.X.AX from the adapter initializion is ignored since some adapters