Commit 1e12c4a9 authored Aug 11, 2016 by Marc Zyngier

genirq: Correctly configure the trigger on chained interrupts



Commit 1e2a7d78 ("irqdomain: Don't set type when mapping an IRQ")
moved the trigger configuration call from the irqdomain mapping to
the interrupt being actually requested.

This patch failed to handle the case where we configure a chained
interrupt, which doesn't get requested through the usual path.

In order to solve this, let's call __irq_set_trigger just before
starting the cascade interrupt. Special care must be taken to
make the flow handler stick, as the .irq_set_type method could
have reset it (it doesn't know we're dealing with a chained
interrupt).

Based on an initial patch by Jon Hunter.

Fixes: 1e2a7d78 ("irqdomain: Don't set type when mapping an IRQ")
Reported-by: John Stultz <john.stultz@linaro.org>
Reported-by: Linus Walleij <linus.walleij@linaro.org>
Tested-by: John Stultz <john.stultz@linaro.org>
Acked-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

parent 694d0d0b

kernel/irq/chip.c

+11 −0

Original line number	Diff line number	Diff line
		@@ -820,6 +820,17 @@ __irq_do_set_handler(struct irq_desc *desc, irq_flow_handler_t handle,
		desc->name = name;

		if (handle != handle_bad_irq && is_chained) {
		/*
		* We're about to start this interrupt immediately,
		* hence the need to set the trigger configuration.
		* But the .set_type callback may have overridden the
		* flow handler, ignoring that we're dealing with a
		* chained interrupt. Reset it immediately because we
		* do know better.
		*/
		__irq_set_trigger(desc, irqd_get_trigger_type(&desc->irq_data));
		desc->handle_irq = handle;

		irq_settings_set_noprobe(desc);
		irq_settings_set_norequest(desc);
		irq_settings_set_nothread(desc);

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