On Thu, 13 Mar 2014, Hans de Goede wrote:
> On 03/13/2014 03:46 PM, Thomas Gleixner wrote:
> >> static int sun4i_irq_map(struct irq_domain *d, unsigned int virq,
> >> irq_hw_number_t hw)
> >> {
> >> - irq_set_chip_and_handler(virq, &sun4i_irq_chip,
> >> - handle_level_irq);
> >> + if (hw == 0) /* IRQ 0, the ENMI needs special handling */
> >> + irq_set_chip_and_handler(virq, &sun4i_irq_chip,
> >> + handle_fasteoi_late_irq);
> >> + else
> >> + irq_set_chip_and_handler(virq, &sun4i_irq_chip,
> >> + handle_level_irq);
> >
> > I wonder what happens when you use the fasteoi handler for all of
> > them.
>
> As mentioned in my previous mail doing an ack (or an eio) seems to
> be unnecessary for all but IRQ 0.
>
> I do wonder if handle_level_irq is the right handle*irq function
> to use in this case, since this is strictly used in the non smp
> case I think that the mask / unmask done by handle_level_irq is
> not necessary for non threaded handlers. So what would be the
> correct handle*irq function to use in this case ?
>
> Note the irqs are level irqs. IOW they may stay asserted while
> the handler runs because of the handler and a new irq raising.
Right. You could be creative and use fasteoi plus an empty eoi
callback in the chip for irq 1-N. That way you only mask and unmask in
the threaded case.
Thanks,
tglx
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