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Date: Fri, 20 Apr 2012 08:38:05 +0200
Message-ID: <CACRpkdYpPLNnuivcN9CsG6ZHsZ7=AOkYv9OSGjfiLFi1ouh03g@mail.gmail.com>
Subject: Re: [PATCH] irqdomain: print a warning if domains contain IRQ 0
From: Linus Walleij <linus.walleij@linaro.org>
To: Grant Likely <grant.likely@secretlab.ca>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Linus Walleij <linus.walleij@stericsson.com>,
        linux-kernel@vger.kernel.org
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On Thu, Apr 19, 2012 at 8:29 PM, Grant Likely <grant.likely@secretlab.ca> wrote:

> This is indeed specific to the legacy domain.  I think the patch is
> good and it will help weed out unintended irq0 users.  However, it
> requires the following additional fix I think.  It will need to be
> tested to make sure it doesn't break PowerPC ISA users.
>
> g.
>
> diff --git a/include/linux/irqdomain.h b/include/linux/irqdomain.h
> index d0995bd..31f1f88 100644
> --- a/include/linux/irqdomain.h
> +++ b/include/linux/irqdomain.h
> @@ -138,7 +138,7 @@ static inline struct irq_domain *irq_domain_add_legacy_isa(
>                                const struct irq_domain_ops *ops,
>                                void *host_data)
>  {
> -       return irq_domain_add_legacy(of_node, NUM_ISA_INTERRUPTS, 0, 0, ops,
> +       return irq_domain_add_legacy(of_node, NUM_ISA_INTERRUPTS-1, 1, 1, ops,
>                                     host_data);

Hm, so what does this do? If I fold it into my patch I need some
kind of blurb...

I'm guessing it bumps the ISA IRQs with one to avoid using IRQ0 which
seems like a valid patch on its own, and that the old code was
used for actively ignoring IRQ 0 on ISA (not used or whatever)?

Yours,
Linus Walleij