Thanks for the detailed answer. if i choose the 2nd approach would it be possible to modify the structrue itself of the pci tree, and not only a specific device number? example: if i add a pci bridge between my board and a graphic card.
Thanks, On Tue, May 8, 2018 at 5:47 PM, Laszlo Ersek <ler...@redhat.com> wrote: > On 05/08/18 16:16, Guy Raviv wrote: > > Hi all, > > > > currently in > > > > \Vlv2DeviceRefCodePkg\AcpiTablesPCAT\HOST_BUS.ASL > > > > The PCI devices are declared statically. > > > > i want to make this declaration dynamic - so that the device number can > change > > > > according according to my hardware setup. Is it possible? > > There are generally two ways for this. > > One is to write the bulk of the ASL like seen here, statically, but all > the customizable values are referenced as external objects / fields. > Then, a platform ACPI DXE driver in the firmware computes those values, > and installs a small SSDT with just those objects. The AML is generated > manually by the firmware, which is super awkward, but due to the small > size of the integer objects etc, it is tolerable. > > A similar approach can be seen e.g. in "OvmfPkg/AcpiPlatformDxe/Qemu.c", > function QemuInstallAcpiSsdtTable(). And the referring ASL code is in > "OvmfPkg/AcpiTables/Dsdt.asl". (Search both for "FWDT".) > > (Note however that said function is not used nowadays on QEMU, because > now QEMU generates *all* of the AML dynamically.) > > The other approach is to process the (static) AML before installing it > with EFI_ACPI_TABLE_PROTOCOL.InstallAcpiTable(). If you know the exact > path to / structure of the AML node that you want to modify, the > EFI_ACPI_SDT_PROTOCOL lets you navigate to the node, and patch it > in-place, in a memory array. Then you can install the modified table > blob with EFI_ACPI_TABLE_PROTOCOL. (Important: do not modify a table > *after* it is installed.) > > One example for the 2nd approach should be > "QuarkPlatformPkg/Acpi/Dxe/AcpiPlatform/AcpiPciUpdate.c". > > Thanks > Laszlo > _______________________________________________ edk2-devel mailing list edk2-devel@lists.01.org https://lists.01.org/mailman/listinfo/edk2-devel
