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    SubjectRe: [PATCH 12/15] sound: add missing HAS_IOPORT and GENERIC_HARDIRQS dependencies
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    On Wednesday 06 February 2013, Heiko Carstens wrote:
    > On Wed, Feb 06, 2013 at 06:26:02PM +0100, Takashi Iwai wrote:
    > > At Thu, 07 Feb 2013 02:13:19 +0100,
    > > Arnd Bergmann wrote:
    > > > No, it is intentional that the CONFIG_HAS_IOPORT symbol refers to
    > > > the fact that you can use the ioport_map function, in order to
    > > > disallow building drivers that depend on this function when it
    > > > is unavailable. I actually want to change this, but in the opposite
    > > > way of what you are proposing:
    > > >
    > > > I think CONFIG_HAS_IOPORT should refer to the fact that the
    > > > inb/outb family of functions are usuable and be unset when
    > > > they are not provided, and I would introduce a new
    > > > CONFIG_HAS_IOPORT_MAP symbol for those (few) platforms that
    > > > have a working inb/outb but no ioport_map.
    > >
    > > Yet another Kconfig, but sounds reasonable :)
    >
    > Right... I just wanted to make s390 compile with the Kconfig methods we use
    > since nearly a decade and not change the world ;)

    Your patch looks fine here, I was just mentioning that this is going to
    change. After my patch, things will be different for s390 as well, because
    it presumably won't provide the inb/outb accessors any more then
    and not set the (new) CONFIG_HAS_IOPORT.

    > > >
    > > > Why not just make CONFIG_GENERIC_HARDIRQS mandatory for all
    > > > platforms. It is use almost everywhere now.
    > >
    > > I wonder it, too...
    >
    > I haven't looked into it, but I doubt if that is possible without large
    > effort, if at all. s390 doesn't have any irq chips, nor something like
    > edge or level triggered irqs.
    > Instead we have floating interrupts. Does that fit into the concept of
    > GENERIC_HARDIRQS at all?
    > If so, we can give it a try, sure. But that won't happen any time soon.
    >
    > Or are you simply proposing we should have both, our own irq handling plus
    > GENERIC_HARDIRQS with dummy functions?

    I think you should use GENERIC_HARDIRQ just for PCI, and rename the s390
    interrupt handling to something that does not conflict. I understand
    that the concepts are quite different, but with PCI support, you actually
    do get all the weird interrupt hardware.
    More importantly, some features provided by GENERIC_HARDIRQ are replacing
    the traditional interfaces now, e.g. devm_request_irq() is actually
    recommended over request_irq() for normal drivers these days, as it
    simplifies the error handling.

    Arnd


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