On Wed, Jun 12, 2019 at 10:06:06AM +1000, Benjamin Herrenschmidt wrote: > On Tue, 2019-06-11 at 18:39 -0500, Bjorn Helgaas wrote: > > This is fine, but can we make a tiny step toward doing this in generic > > code instead of adding more arch-specific stuff? > > > > E.g., evaluate the _DSM in the generic acpi_pci_root_add(), set a > > "preserve_config" bit in the struct acpi_pci_root, and test the bit > > here? > > I'd rather have the flag in the host bridge no ? Oh, of course, that would make more sense. > Talking of which, look at the ongoing discussion I have with Lorenzo > when it comes to pci_bus_claim_resources vs. what x86 does, I'd love > for you to chime in. I'd like to try to consolidate things further > accross architectures but there might be reasons I don't see as to why > things are different in that area, so ... I don't know any reasons why things are different per arch. In most cases I suspect FUD. Speaking of which, *this* patch looks like FUD because it essentially says "Linux shouldn't change the PCI configuration on this system" but it offers no explanation of *why* the config needs to be preserved. I would really like some note like "run-time firmware depends on the addresses of device X". Bjorn
