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