[Bug 2167567] Re: [Resolute] Enable Device Tree overlays on amd64 for PCIe-attached FPGAs

** Tags added: kernel-daily-bug -- You received this bug notification because you are subscribed to linux in Ubuntu. Matching subscriptions: Bgg, Bmail, Nb https://bugs.launchpad.net/bugs/2167567 Title: [Resolute] Enable Device Tree overlays on amd64 for PCIe-attached FPGAs Status in linux package in Ubuntu: Confirmed Bug description: [Impact] AMD Embedded+ platforms need Device Tree support on x86 to describe IP blocks implemented in PCIe-attached FPGAs. Loading an overlay for a particular FPGA design allows existing Device Tree-based drivers to be reused without porting each driver to ACPI. The required configuration options are currently disabled or absent from the amd64 configuration. [Fix] Enable the following options for amd64 in linux-amd-embedded: CONFIG_OF=y Enable the core Device Tree infrastructure used to represent device nodes and properties in the kernel. CONFIG_OF_OVERLAY=y Enable support for applying Device Tree overlays at runtime. This also selects the dynamic tree, flattened tree and phandle resolution support required by overlays. CONFIG_DTC=y Enable the Device Tree compiler used during the kernel build to compile Device Tree sources into flattened binary form. This option is also selected through CONFIG_OF_FLATTREE. CONFIG_PCI_DYNAMIC_OF_NODES=y Enable creation of Device Tree nodes for PCI devices, providing nodes to which an FPGA driver can attach an overlay describing downstream devices. This requires CONFIG_OF_IRQ and selects CONFIG_OF_DYNAMIC. Synchronize the dependent amd64 configuration entries exposed by enabling CONFIG_OF. Most newly visible optional drivers remain explicitly disabled. Keep all overrides in the linux-amd-embedded configuration. The arm64 configuration and shared generic configuration remain unchanged. This change does not add an FPGA Discovery driver. [Test Plan] Export the amd64 configuration and run olddefconfig. Verify that all four requested options remain set to y. Run the Ubuntu annotations check against the resulting configuration. Compare the arm64 configuration before and after the change. These configuration checks pass. The arm64 export is identical. Full kernel build and runtime overlay testing remain to be done. [Where problems could occur] Enabling CONFIG_OF exposes additional configuration symbols and automatically selects supporting infrastructure. Incorrect or incomplete annotations could cause configuration checks to fail or produce unintended amd64 configuration changes. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2167567/+subscriptions