I'd like to hear Arnd's opinion, too. If we do add LEGACY_PCI, II'd like to hear Arnd's opinion on this but you're the PCI maintainerok if the PCI maintainers decide otherwise.I don't really like the "LEGACY_PCI" Kconfig option. "Legacy" just
means something old and out of favor; it doesn't say*what* that
something is.
I think you're specifically interested in I/O port space usage, and it
seems that you want all PCI drivers that*only* use I/O port space to
depend on LEGACY_PCI? Drivers that can use either I/O or memory
space or both would not depend on LEGACY_PCI? This seems a little
murky and error-prone.
so of course your buy-in would be quite important for such an option.
think we need a clear guide for when to use it, e.g., "a PCI driver
that uses inb() must depend on LEGACY_PCI" or whatever it is.
I must be missing something because I don't see what we gain from
this. We have PCI drivers, e.g., megaraid [1], for devices that have
either MEM or I/O BARs. I think we want to build drivers like that on
any arch that supports PCI.
If the arch doesn't support I/O port space, devices that only have I/O
BARs won't work, of course, and hopefully the PCI core and driver can
figure that out and gracefully fail the probe.
But that same driver should still work with devices that have MEM
BARs. If inb() isn't always present, I guess we could litter these
drivers with #ifdefs, but that would be pretty ugly.
IMO inb() should
be present but do something innocuous like return ~0, as it would if
I/O port space is supported but there's no device at that address.
[1]https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/scsi/megaraid.c?id=v5.15#n4210