Re: [PATCH] ata: Don't use NO_IRQ in pata_of_platform driver

James Bottomley
2011-12-05T19:19:21Z

On Mon, 2011-12-05 at 18:45 +0000, Alan Cox wrote:
> > But as you illustrated, there is a large number of drivers that already
> > assume no IRQ is < 0, even if they don't use any IRQ #0 themselves.
> > That is a much bigger problem to fix.
>
> And a much larger number assuming the reverse is true which are hiding
> potential bugs on ARM.
>
> Looking at the serial stuff the best checks appear to be looking at
> "irq", "-1" and NO_IRQ.
>
> For migration stuff that's doing broken things like
>
> if (irq < 0)
>
> can be changed to
>
> if (irq <= 0)
>
> and that can be done before NO_IRQ itself is nailed on ARM and PA-RISC.

To be honest, we don't care very much. Parisc interrupts are cascading
and mostly software assigned (except our EIEM which we keep internal).
We use a base offset at 16 or 64 (depending on GSC presence or not) so
IRQs 0-15 aren't legal on parisc either (we frob some of the hard coded
ISA interrupts on the WAX eisa bus).

We use NO_IRQ as an IRQ assignment error return and that's about it (and
that error shouldn't ever really occur).

James