On Thu, Jan 06, 2022 at 05:41:00PM +0000, John Garry wrote: > On 05/01/2022 19:47, Bjorn Helgaas wrote: > > 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 > > > > That driver would prob not be used on systems which does not support PIO, > and so could have a HAS_IOPORT dependency. But it is not strictly necessary. I don't want the path of "this driver isn't needed because the device is unlikely to be used on this arch." Maybe it's not _always_ possible, but if the device can be plugged into the platform, I think we should be able to build the driver for it. If the device requires I/O port space and the platform doesn't support it, the PCI core or the driver should detect that and give a useful diagnostic. Bjorn
