From 6f20526da6631302cac8a79fd2392bddd2514948 Mon Sep 17 00:00:00 2001 From: Gerd Hoffmann Date: Wed, 7 Sep 2022 11:15:04 +0200 Subject: [PATCH 22/22] OvmfPkg/QemuVideoDxe: fix bochs mode init Add VgaInb() helper function to read vga registers. With that in place fix the unblanking. We need to put the ATT_ADDRESS_REGISTER flip flop into a known state, which is done by reading the INPUT_STATUS_1_REGISTER. Reading the INPUT_STATUS_1_REGISTER only works when the device is in color mode, so make sure that bit (0x01) is set in MISC_OUTPUT_REGISTER. Currently the mode setting works more by luck because ATT_ADDRESS_REGISTER flip flop happens to be in the state we need. Signed-off-by: Gerd Hoffmann Reviewed-by: Ard Biesheuvel (cherry picked from commit 512042eba87ff97a4820a55cf3b1a89a8afd1cc7) --- OvmfPkg/QemuVideoDxe/Driver.c | 34 +++++++++++++++++++++++++++++++++- 1 file changed, 33 insertions(+), 1 deletion(-) diff --git a/OvmfPkg/QemuVideoDxe/Driver.c b/OvmfPkg/QemuVideoDxe/Driver.c index b91909a14e59..c28171d13719 100644 --- a/OvmfPkg/QemuVideoDxe/Driver.c +++ b/OvmfPkg/QemuVideoDxe/Driver.c @@ -984,6 +984,34 @@ VgaOutb ( } } +STATIC +UINT8 +VgaInb ( + QEMU_VIDEO_PRIVATE_DATA *Private, + UINTN Reg + ) +{ + EFI_STATUS Status; + UINT8 Data; + + if (Private->Variant == QEMU_VIDEO_BOCHS_MMIO) { + Data = 0; + Status = Private->PciIo->Mem.Read ( + Private->PciIo, + EfiPciIoWidthUint8, + PCI_BAR_IDX2, + 0x400 - 0x3c0 + Reg, + 1, + &Data + ); + ASSERT_EFI_ERROR (Status); + } else { + Data = inb (Private, Reg); + } + + return Data; +} + VOID InitializeBochsGraphicsMode ( QEMU_VIDEO_PRIVATE_DATA *Private, @@ -998,7 +1026,11 @@ InitializeBochsGraphicsMode ( ModeData->ColorDepth )); - /* unblank */ + /* set color mode */ + VgaOutb (Private, MISC_OUTPUT_REGISTER, 0x01); + + /* reset flip flop + unblank */ + VgaInb (Private, INPUT_STATUS_1_REGISTER); VgaOutb (Private, ATT_ADDRESS_REGISTER, 0x20); BochsWrite (Private, VBE_DISPI_INDEX_ENABLE, 0); -- 2.37.3