On Thu, 2016-02-18 at 18:02 +0100, Laszlo Ersek wrote: > > with Ray's change in the generic PCI bus driver, *must* all PciIo-based > device drivers be updated? Is this a (bug-)compatible change, or does it > regress existing drivers (perhaps by triggering their hidden bugs)?
I wouldn't expect existing drivers to break no, as I don't expect them to look at the AddressTranslation field and it's 0 anyway on existing platforms. Of course they have to be updated to work on non-1:1 platforms. > If this PciIo change has potential to expose bugs or invalid silent > assumptions in other drivers, then I think the patch should not be > committed in isolation. It should be part of a series that addresses > said assumptions in all dependent drivers that are present in the open > source edk2 tree. I am not aware of such bugs or silent assumptions. I had the opportunity to look at a couple of vendor drivers as well and they also don't seem to make such problematic assumptions either. > I believe, for QemuVideoDxe, running on > - qemu-system-(i386|x86_64), i440fx and q35 machine types, or > - qemu-system-(arm|aarch64), "virt" machine type, > > the translation offset between CPU and device MMIO is, in practice, > zero, so I guess in practice QemuVideoDxe won't break. > > But, it would be nice to see confirmation (plus in the long term, > QemuVideoDxe should be updated nonetheless) I agree but overall I think this is pretty safe. Cheers, Ben. _______________________________________________ edk2-devel mailing list [email protected] https://lists.01.org/mailman/listinfo/edk2-devel
