Re: [PATCH] irq: Add a new IRQF_ACK_BEFORE_UNMASK irq flag

[Russell King - ARM Linux <linux@arm.linux.org.uk>]

On Wed, Mar 12, 2014 at 11:38:24AM +0100, Thomas Gleixner wrote:
> If the interrupt chip has this behaviour then handle_level_irq as the
> flow handler is the wrong thing to start with because it always acks
> before calling the handler.

This sounds like the situation with the Dove PMC irqchip too, except
that it has the additional complication that "acking" any interrupt is
potentially distructive to other pending interrupts, so should be done
as infrequently as possible.

> +void unmask_threaded_irq(struct irq_desc *desc)
> +{
> +	struct irq_chip *chip = desc->irq_data.chip;
> +
> +	if (chip->flags & IRQCHIP_EOI_THREADED)
> +		chip->irq_eoi(&desc->irq_data);
> +
> +	if (chip->irq_unmask) {
> +		desc->irq_data.chip->irq_unmask(&desc->irq_data);

ITYM:
		chip->irq_unmask(&desc->irq_data);

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