Bjorn Helgaas wrote: > On Fri, Sep 09, 2022 at 12:20:45PM +0200, Robert Richter wrote: > > On 08.09.22 12:45:16, Dan Williams wrote: > > > Rafael J. Wysocki wrote: > > > > On Thu, Sep 8, 2022 at 8:05 AM Dan Williams <dan.j.williams@xxxxxxxxx> wrote: > > > > > > > > > > Robert Richter wrote: > > > > > > A lookup of a host bridge's corresponding acpi device (struct > > > > > > acpi_device) is not possible, for example: > > > > > > > > > > > > adev = ACPI_COMPANION(&host_bridge->dev); > > > > > > > > > > > > This could be useful to find a host bridge's fwnode handle and to > > > > > > determine and call additional host bridge ACPI parameters and methods > > > > > > such as HID/CID or _UID. > > > ... > > No, it is x86. And true, it is set. So this series is actually working > > without this patch. It can be dropped. > > > > Now, I just checked my logs. The reason I was adding this is that > > during code development I modified the code to have bridge->dev.parent > > set. Then, the fwnode is not linked. I later dropped that change but > > kept this patch. > > If this patch does the same thing as the ACPI_COMPANION_SET() in > several pcibios_root_bridge_prepare() implementations, I would love to > keep this patch, which does it in a generic place, and drop the > corresponding code from those arch-specific functions. > > But I don't understand the fwnode stuff well enough to know if this is > feasible. I took a brief look, but I could not convince myself that these lookups: arch/ia64/pci/pci.c ((struct pci_controller *) bridge->bus->sysdata)->companion arch/loongarch/pci/acpi.c to_acpi_device(((struct pci_config_window *) bridge->bus->sysdata)->parent) arch/arm64/kernel/pci.c to_acpi_device(((struct pci_config_window *) bridge->bus->sysdata)->parent) arch/x86/pci/acpi.c ((struct pci_sysdata *) bridge->bus->sysdata)->companion ...are identical to what acpi_pci_root_add() used to create the acpi_pci_root.
