On Sat, Jan 30, 2016 at 07:30:27AM -0600, Bjorn Helgaas wrote: [...] > > Most non-UEFI firmwares I have seen on ARM rely on device specific > > driver like synopsys etc. to do the device initialization and ask > > kernel to do the enumeration. > > > > ACPI systems on the other hand handle the resource assignment before > > the OS starts. > > My guess is that this is more of a tradition than anything actually > required by the spec. I share your opinion, and that tradition on ARM64 should be built on top of existing DT based systems where the bootloader assigns *NOTHING* in 90% of designs. That's why I want to see resource claiming carried out by default on ACPI on ARM64, this would foster the tradition :), hopefully. > The bottom line is that Linux can't rely on much consistency across > the universe of architectures and firmwares. I think the only thing > that really makes sense for us to do is: > > - Read whatever assignments the firmware may have made > - Keep them unchanged if they seem sensible Here I take "sensible" as "it can be successfully claimed" - ie the resource is allocated in a valid way, though it may not be optimal (eg bridge window apertures). > - Reassign them if they aren't sensible And we reassign whatever can't be successfully claimed. Yes, it seems like the best approach and likely the only viable one. Thanks, Lorenzo -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
