* Maciej W. Rozycki <ma...@linux-mips.org> wrote:
> On Mon, 27 Oct 2014, Ingo Molnar wrote:
>
> > What's the effect of this change on the output for non-8259A irq
> > controllers?
>
> Good question, I didn't expect any other IRQ controller to be used for
> ISA interrupts (the APIC is handled elsewhere). I have checked the
> sources and the only other controller that can be used for `legacy_pic'
> is `dummy_irq_chip' (cf. `default_legacy_pic' vs `null_legacy_pic' in
> arch/x86/kernel/i8259.c). That affects `init_ISA_irqs' only (the other
> place, `make_8259A_irq', has a reference to `i8259A_chip' hardcoded).
>
> In this case the output would change from "dummy-dummy" to "dummy",
> which IMHO has just as much value as the change from "XT-PIC-XT-PIC" to
> "XT-PIC". However I don't think you'd be able to request such IRQs so
> they will never show up in /proc/interrupts, making this observation
> largely irrelevant. If you think I may be wrong here, then can you
> please find such a system and try this change with it (or can someone
> else reading this make this check for me by any chance)? Unfortunately
> all x86 hardware I have does have an 8259A pair.
>
> Also please note that both places explicitly refer to the name of the
> IRQ chip being installed as the name of the handler as well, with
> `i8259A_chip.name' and `chip->name' respectively, this is hardcoded.
> So no matter which chip is used there'll be a duplicate name in
> /proc/interrupts.
>
> Does this answer address your concern?
Yeah, it addresses it, I'll queue up your fix, thanks!
Ingo
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