Re: [PATCH 4/5] Centralise NO_IRQ definition

From: David Woodhouse
Date: Tue Nov 22 2005 - 06:14:08 EST

On Mon, 2005-11-21 at 22:20 +0000, Alan Cox wrote:
> > Yes, G5 powermacs have the SATA controller on irq 0. So if we can't
> > use irq 0, I can't get to my hard disk. :) Other powermacs also use
> > irq 0 for various things, as do embedded PPC machines.
> G5 powermacs have the SATA controller on physical IRQ value 0. Linux IRQ
> values don't need to exactly map. One of the x86 ports handles 'real IRQ
> 0' exactly this way. Its a cookie. Sure would benefit from a function
> for turning an IRQ into a description as a cleanup.

Remapping in that way sounds like a half-arsed hack to work around the
problem which Matthew is trying to fix properly by using NO_IRQ == -1.

Yes, there are drivers which are currently broken and assume irq 0 is
'no irq'. They are broken. Let's just fix them and not continue the


To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at