mirror of https://github.com/acidanthera/audk.git
662bd0da7f
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.chen@intel.com> Cc: Jordan Justen <jordan.l.justen@intel.com> Cc: Laszlo Ersek <lersek@redhat.com> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Anthony Perard <anthony.perard@citrix.com> Cc: Julien Grall <julien.grall@arm.com> Cc: Marc-André Lureau <marcandre.lureau@redhat.com> Cc: Stefan Berger <stefanb@linux.ibm.com> Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=1880 Reviewed-by: Laszlo Ersek <lersek@redhat.com> Message-Id: <20190606074237.81492-1-marc.w.chen@intel.com> Signed-off-by: Laszlo Ersek <lersek@redhat.com> |
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| .. | ||
| ComponentName.c | ||
| Driver.c | ||
| Gop.c | ||
| Initialize.c | ||
| Qemu.h | ||
| QemuVideoDxe.inf | ||
| VbeShim.asm | ||
| VbeShim.c | ||
| VbeShim.h | ||
| VbeShim.sh | ||