From 237bb9d0be75978a773a084fe739df261742b913 Mon Sep 17 00:00:00 2001
From: klu2 <klu2@6f19259b-4bc3-4df7-8a09-765794883524>
Date: Mon, 2 Mar 2009 15:03:37 +0000
Subject: [PATCH] Fix bug of wrong stack16 stack for thunk call. This may cause
 Duet failed to enter graphic mode under Qemu simulator or some platforms.

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@7771 6f19259b-4bc3-4df7-8a09-765794883524
---
 DuetPkg/BiosVideoThunkDxe/BiosVideo.c       | 10 +++++++-
 DuetPkg/BiosVideoThunkDxe/LegacyBiosThunk.c | 27 +++++++++------------
 2 files changed, 21 insertions(+), 16 deletions(-)

diff --git a/DuetPkg/BiosVideoThunkDxe/BiosVideo.c b/DuetPkg/BiosVideoThunkDxe/BiosVideo.c
index 6a8e55a034..7053a0002c 100644
--- a/DuetPkg/BiosVideoThunkDxe/BiosVideo.c
+++ b/DuetPkg/BiosVideoThunkDxe/BiosVideo.c
@@ -1043,6 +1043,7 @@ BiosVideoCheckForVbe (
   VESA_BIOS_EXTENSIONS_VALID_EDID_TIMING ValidEdidTiming;
   EFI_GRAPHICS_OUTPUT_PROTOCOL_MODE      *GraphicsOutputMode;
 
+  DEBUG ((EFI_D_INFO, "Enter BiosVideoCheckForVbe()\n"));
   //
   // Allocate buffer under 1MB for VBE data structures
   //
@@ -1095,26 +1096,33 @@ BiosVideoCheckForVbe (
   Regs.X.ES = EFI_SEGMENT ((UINTN) BiosVideoPrivate->VbeInformationBlock);
   Regs.X.DI = EFI_OFFSET ((UINTN) BiosVideoPrivate->VbeInformationBlock);
 
+  DEBUG ((EFI_D_INFO, "Before VESA!\n"));
   LegacyBiosInt86 (BiosVideoPrivate, 0x10, &Regs);
-  
+  DEBUG ((EFI_D_INFO, "Call VESA! Return Status=0x%X\n", Regs.X.AX));
+  DEBUG ((EFI_D_INFO, "Call VESA! VESA Signature =0x%X\n", BiosVideoPrivate->VbeInformationBlock->VESASignature));
+  DEBUG ((EFI_D_INFO, "Call VESA! VESA Version =0x%X\n", BiosVideoPrivate->VbeInformationBlock->VESAVersion));
+    
   Status = EFI_DEVICE_ERROR;
 
   //
   // See if the VESA call succeeded
   //
   if (Regs.X.AX != VESA_BIOS_EXTENSIONS_STATUS_SUCCESS) {
+    DEBUG ((EFI_D_INFO, "Fail to call VESA! Status=0x%X\n", Regs.X.AX));
     return Status;
   }
   //
   // Check for 'VESA' signature
   //
   if (BiosVideoPrivate->VbeInformationBlock->VESASignature != VESA_BIOS_EXTENSIONS_VESA_SIGNATURE) {
+    DEBUG ((EFI_D_INFO, "Fail to check VESA signature!\n"));
     return Status;
   }
   //
   // Check to see if this is VBE 2.0 or higher
   //
   if (BiosVideoPrivate->VbeInformationBlock->VESAVersion < VESA_BIOS_EXTENSIONS_VERSION_2_0) {
+    DEBUG ((EFI_D_INFO, "VBE version is little than 2.0!\n"));
     return Status;
   }
 
diff --git a/DuetPkg/BiosVideoThunkDxe/LegacyBiosThunk.c b/DuetPkg/BiosVideoThunkDxe/LegacyBiosThunk.c
index b8603426c6..08ed35c1f4 100644
--- a/DuetPkg/BiosVideoThunkDxe/LegacyBiosThunk.c
+++ b/DuetPkg/BiosVideoThunkDxe/LegacyBiosThunk.c
@@ -146,17 +146,17 @@ LegacyBiosInt86 (
   BOOLEAN               Ret;
   UINT16                *Stack16;
   
-  Regs->X.Flags.Reserved1 = 1;
-  Regs->X.Flags.Reserved2 = 0;
-  Regs->X.Flags.Reserved3 = 0;
-  Regs->X.Flags.Reserved4 = 0;
-  Regs->X.Flags.IOPL      = 3;
-  Regs->X.Flags.NT        = 0;
-  Regs->X.Flags.IF        = 1;
-  Regs->X.Flags.TF        = 0;
-  Regs->X.Flags.CF        = 0;
-
   ZeroMem (&ThunkRegSet, sizeof (ThunkRegSet));
+  ThunkRegSet.E.EFLAGS.Bits.Reserved_0 = 1;
+  ThunkRegSet.E.EFLAGS.Bits.Reserved_1 = 0;
+  ThunkRegSet.E.EFLAGS.Bits.Reserved_2 = 0;
+  ThunkRegSet.E.EFLAGS.Bits.Reserved_3 = 0;
+  ThunkRegSet.E.EFLAGS.Bits.IOPL       = 3;
+  ThunkRegSet.E.EFLAGS.Bits.NT         = 0;
+  ThunkRegSet.E.EFLAGS.Bits.IF         = 1;
+  ThunkRegSet.E.EFLAGS.Bits.TF         = 0;
+  ThunkRegSet.E.EFLAGS.Bits.CF         = 0;
+  
   ThunkRegSet.E.EDI  = Regs->E.EDI;
   ThunkRegSet.E.ESI  = Regs->E.ESI;
   ThunkRegSet.E.EBP  = Regs->E.EBP;
@@ -167,8 +167,6 @@ LegacyBiosInt86 (
   ThunkRegSet.E.DS   = Regs->E.DS;
   ThunkRegSet.E.ES   = Regs->E.ES;
 
-  CopyMem (&(ThunkRegSet.E.EFLAGS), &(Regs->E.EFlags), sizeof (UINT32));
- 
   //
   // The call to Legacy16 is a critical section to EFI
   //
@@ -184,16 +182,15 @@ LegacyBiosInt86 (
   ASSERT_EFI_ERROR (Status);
   
   Stack16 = (UINT16 *)((UINT8 *) BiosDev->ThunkContext->RealModeBuffer + BiosDev->ThunkContext->RealModeBufferSize - sizeof (UINT16));
-  Stack16 -= sizeof (ThunkRegSet.E.EFLAGS) / sizeof (UINT16);
-  CopyMem (Stack16, &ThunkRegSet.E.EFLAGS, sizeof (ThunkRegSet.E.EFLAGS));
 
   ThunkRegSet.E.SS   = (UINT16) (((UINTN) Stack16 >> 16) << 12);
   ThunkRegSet.E.ESP  = (UINT16) (UINTN) Stack16;
+
   ThunkRegSet.E.Eip  = (UINT16)((UINT32 *)NULL)[BiosInt];
   ThunkRegSet.E.CS   = (UINT16)(((UINT32 *)NULL)[BiosInt] >> 16);
   BiosDev->ThunkContext->RealModeState = &ThunkRegSet;
   AsmThunk16 (BiosDev->ThunkContext);
-
+  
   //
   // Restore protected mode interrupt state
   //
-- 
2.39.2