On 06/06/19 09:42, Marc W Chen wrote: > Query the supported attributes firstly, then bitwise AND (&) both VGA_IO > and VGA_IO_16. Since the supported attributes should only have one of > VGA_IO or VGA_IO_16 set, the result of bitwise AND (&) is either VGA_IO > or IO_16. Then the result can be passed to PciIo->Attributes() to set the > attributes. > > Device driver should consider both since the mReserveVgaAliases in > PciBusDxe driver is default FALSE(implies that device driver can only set > VGA_IO_16 to PCI_ROOT_BRIDGE), and Platform code may not return > EFI_RESERVE_VGA_IO_ALIAS in GetPlatformPolicy of PciPlatformProtocol to > make mReserveVgaAliases become TRUE(implies that device driver can only > set VGA_IO to PCI_ROOT_BRIDGE), Currently OvmfPkg doesn't have problem > due to it has hard code value for PCI_ROOT_BRIDGE's attributes field, so > an IO access by PciIoProtocol will be successed due to > RootBridgeIoCheckParameter of PciRootBridgeIo.c will always get pass > result for legacy IO access. > > Usually the attributes field of PCI_ROOT_BRIDGE should be 0, in that case > it will have issue since the VGA_IO may not be able to be enabled, then > IO access by PciIoProtocol will be failed, hence the QemuVideoDxe driver > will not work fine. > > Signed-off-by: Marc Chen <marc.w.c...@intel.com> > Cc: Jordan Justen <jordan.l.jus...@intel.com> > Cc: Laszlo Ersek <ler...@redhat.com> > Cc: Ard Biesheuvel <ard.biesheu...@linaro.org> > Cc: Anthony Perard <anthony.per...@citrix.com> > Cc: Julien Grall <julien.gr...@arm.com> > Cc: Marc-André Lureau <marcandre.lur...@redhat.com> > Cc: Stefan Berger <stef...@linux.ibm.com> > Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=1880 > --- > OvmfPkg/QemuVideoDxe/Driver.c | 22 +++++++++++++++++++++- > 1 file changed, 21 insertions(+), 1 deletion(-) > > diff --git a/OvmfPkg/QemuVideoDxe/Driver.c b/OvmfPkg/QemuVideoDxe/Driver.c > index e8a613ef33..522110ef4e 100644 > --- a/OvmfPkg/QemuVideoDxe/Driver.c > +++ b/OvmfPkg/QemuVideoDxe/Driver.c > @@ -201,6 +201,7 @@ QemuVideoControllerDriverStart ( > PCI_TYPE00 Pci; > QEMU_VIDEO_CARD *Card; > EFI_PCI_IO_PROTOCOL *ChildPciIo; > + UINT64 SupportedVgaIo; > > OldTpl = gBS->RaiseTPL (TPL_CALLBACK); > > @@ -277,13 +278,32 @@ QemuVideoControllerDriverStart ( > goto ClosePciIo; > } > > + // > + // Get supported PCI attributes > + // > + Status = Private->PciIo->Attributes ( > + Private->PciIo, > + EfiPciIoAttributeOperationSupported, > + 0, > + &SupportedVgaIo > + ); > + if (EFI_ERROR (Status)) { > + goto ClosePciIo; > + } > + > + SupportedVgaIo &= (UINT64)(EFI_PCI_IO_ATTRIBUTE_VGA_IO | > EFI_PCI_IO_ATTRIBUTE_VGA_IO_16); > + if (SupportedVgaIo == 0) { > + Status = EFI_UNSUPPORTED; > + goto ClosePciIo; > + } > + > // > // Set new PCI attributes > // > Status = Private->PciIo->Attributes ( > Private->PciIo, > EfiPciIoAttributeOperationEnable, > - EFI_PCI_DEVICE_ENABLE | > EFI_PCI_IO_ATTRIBUTE_VGA_MEMORY | EFI_PCI_IO_ATTRIBUTE_VGA_IO, > + EFI_PCI_DEVICE_ENABLE | > EFI_PCI_IO_ATTRIBUTE_VGA_MEMORY | SupportedVgaIo, > NULL > ); > if (EFI_ERROR (Status)) { >
Reviewed-by: Laszlo Ersek <ler...@redhat.com> I will keep this patch tagged on my end, so that I can push it once edk2-stable201905 has been tagged. Should I forget, please ping me. Thanks Laszlo -=-=-=-=-=-=-=-=-=-=-=- Groups.io Links: You receive all messages sent to this group. View/Reply Online (#41986): https://edk2.groups.io/g/devel/message/41986 Mute This Topic: https://groups.io/mt/31948697/21656 Group Owner: devel+ow...@edk2.groups.io Unsubscribe: https://edk2.groups.io/g/devel/unsub [arch...@mail-archive.com] -=-=-=-=-=-=-=-=-=-=-=-
