On Mon, Sep 4, 2023, at 08:01, Ian Abbott wrote: > On 04/09/2023 12:23, Niklas Schnelle wrote: >> On Mon, 2023-09-04 at 11:10 +0100, Ian Abbott wrote: > > Thanks for the confirmation. Will it be safe to assume that anything > that selects ISA will also select HAS_IOPORT? That is trivially the > case for arch/{alpha,arm,x86}; arch/mips explicitly selects HAS_IOPORT > if ISA is selected; arch/powerpc explicitly selects HAS_IOPORT if PCI is > selected and it is only possible to configure ISA if PPC_CHRP is > configured which selects FORCE_PCI and therefore selects PCI and > therefore selects HAS_IOPORT; arch/um does not select HAS_IOPORT and > although it has a 'config ISA', nothing appears to select it. None of > the remaining arch/* have 'select ISA'. Yes, I think that will always be a safe assumption, ISA without port I/O is just not a sensible configuration. A few of the later ISA devices use PCI style memory mapped I/O, but I can't think of any driver that doesn't also require port I/O, and you wouldn't find ISA slots in a system that lacks support for port I/O. Arnd