On 2014-1-21 2:39, Arnd Bergmann wrote: > On Monday 20 January 2014, Hanjun Guo wrote: >>>> acpi_register_ioapic()/acpi_unregister_ioapic() will be used for IOAPIC >>>> hotplug and GIC distributor is something like IOAPIC on x86, so I think >>>> these two functions can be reserved for future use. >>> But GIC is not hotplugged, is it? It still sounds x86 specific to me. >> >> Well, if we want to do physical CPU hotplug on ARM/ARM64 (maybe years >> later?), >> then GIC add/remove is needed because we have to remove GIC >> on the SoC too when we remove the physical CPU. > > In general, I recommend not planning for the future in kernel code when you > don't know what is going to happen. It's always easy enough to change > things once you get there, as long as no stable ABI is involved. Ok, I agree with you. > > I just looked at the caller of these functions, and found a self-contained > PCI driver in drivers/pci/ioapic.c, which uses two sepate PCI classes for > ioapic and ioxapic. I think it's a safe assumption to say that even if we > get ARM CPU+GIC hotplug, that would not use the same ioapic driver. This > driver is currently marked X86-only, and that should probably stay this way, > so you won't need the hooks. Will find a suitable way to fix that in next version, thanks for you comments :) Hanjun -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
