Re: [PATCH 1/6] irqchip: add the Alpine MSIX interrupt controller

From: Antoine Tenart
Date: Mon Feb 08 2016 - 09:48:41 EST


On Mon, Feb 08, 2016 at 02:29:12PM +0000, Marc Zyngier wrote:
> On 08/02/16 14:17, Antoine Tenart wrote:
> > Thomas,
> >
> > On Mon, Feb 08, 2016 at 11:31:47AM +0100, Thomas Gleixner wrote:
> >> On Mon, 8 Feb 2016, Antoine Tenart wrote:
> >>> +static int alpine_msix_set_affinity(struct irq_data *irq_data,
> >>> + const struct cpumask *mask, bool force)
> >>> +{
> >>> + int ret;
> >>> +
> >>> + ret = irq_chip_set_affinity_parent(irq_data, mask, force);
> >>> + return ret == IRQ_SET_MASK_OK ? IRQ_SET_MASK_OK_DONE : ret;
> >>
> >> What's the point of this exercise? Why can't you just set the affinity
> >> callback to irq_chip_set_affinity_parent() ?
> >
> > That's what done in irq-gic-v2m.c. Besides that, I see no point. I'll
> > update for v2.
>
> That's because there is no need to do another compose_msi_msg/write_msg
> in msi_domain_set_affinity() once the affinity has been updated at the
> GIC level. Alternatively, updating the GIC driver to always return
> IRQ_SET_MASK_OK_DONE would be perfectly acceptable.

I'm using drivers/irqchip/irq-gic-v3.c which is indeed always returning
IRQ_SET_MASK_OK. I'll make a new patch in the v2 of this series to
return IRQ_SET_MASK_OK_DONE instead in the GIC driver (and then patch
irq-gic-v2m.c).

Thanks,

Antoine

--
Antoine Ténart, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com

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