From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Jon Smirl <jonsmirl@gmail.com>
Cc: PowerPC dev list <Linuxppc-dev@ozlabs.org>
Subject: Re: IRQs in i2c-mpc.c
Date: Sun, 11 Nov 2007 17:27:51 +1100 [thread overview]
Message-ID: <1194762471.21340.39.camel@pasglop> (raw)
In-Reply-To: <9e4733910711101544v178e29cer4e53577c011e89f7@mail.gmail.com>
> irq_of_parse_and_map() returns NO_IRQ when the irq parameter is missing.
>
> This API appears to be broken. In asm-powerpc/irq.h NO_IRQ is defined
> as (0). There is no way to tell an error in the attribute from a valid
> attribute selecting interrupt zero.
No, it is not broken. Interrupt numbers in arch/powerpc are virtually
mapped and 0 is never a legal value, thus NO_IRQ is 0. This was done in
part because Linus wanted it that way.
The hardware number can perfectly be 0 though, that's a different thing,
and has nothing to do with what you pass to request_irq().
Ben.
next prev parent reply other threads:[~2007-11-11 6:27 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-11-10 19:44 IRQs in i2c-mpc.c Jon Smirl
2007-11-10 23:09 ` Kumar Gala
2007-11-10 23:16 ` Jon Smirl
2007-11-10 23:18 ` Kumar Gala
2007-11-10 23:44 ` Jon Smirl
2007-11-11 6:27 ` Benjamin Herrenschmidt [this message]
2007-11-11 15:34 ` Jon Smirl
2007-11-11 20:44 ` Benjamin Herrenschmidt
2007-11-11 6:26 ` Benjamin Herrenschmidt
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