Patch "genirq: Don't return ENOSYS in irq_chip_retrigger_hierarchy" has been added to the 4.1-stable tree

This is a note to let you know that I've just added the patch titled

genirq: Don't return ENOSYS in irq_chip_retrigger_hierarchy

to the 4.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
genirq-don-t-return-enosys-in-irq_chip_retrigger_hierarchy.patch
and it can be found in the queue-4.1 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Grygorii Strashko <[email protected]>
Date: Fri, 14 Aug 2015 15:20:25 +0300
Subject: genirq: Don't return ENOSYS in irq_chip_retrigger_hierarchy

From: Grygorii Strashko <[email protected]>

commit 6d4affea7d5aa5ca5ff4c3e5fbf3ee16801cc527 upstream.

irq_chip_retrigger_hierarchy() returns -ENOSYS if it was not able to find at least one .irq_retrigger() callback implemented in the IRQ domain hierarchy.

That's wrong, because check_irq_resend() expects a 0 return value from the callback in case that the hardware assisted resend was not possible. If the return value is non zero the core code assumes hardware resend success and the software resend is not invoked.

This results in lost interrupts on platforms where none of the parent irq chips in the hierarchy implements the retrigger callback.

This is observable on TI OMAP, where the hierarchy is:

ARM GIC <- OMAP wakeupgen <- TI Crossbar

Return 0 instead so the software resend mechanism gets invoked.

[ tglx: Massaged changelog ]

---
 kernel/irq/chip.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

@@ -946,7 +946,7 @@ int irq_chip_retrigger_hierarchy(struct
 		if (data->chip && data->chip->irq_retrigger)
 			return data->chip->irq_retrigger(data);
 
-	return -ENOSYS;
+	return 0;
 }
 
 /**

Patches currently in stable-queue which might be from grygorii.strashko at ti.com are

queue-4.1/irqchip-crossbar-restore-the-mask-on-suspend-behaviour.patch queue-4.1/genirq-don-t-return-enosys-in-irq_chip_retrigger_hierarchy.patch queue-4.1/irqchip-crossbar-restore-set_wake-functionality.patch queue-4.1/irqchip-crossbar-restore-the-irq_set_type-mechanism.patch queue-4.1/arm-dts-dra7-fix-broken-pbias-device-creation.patch queue-4.1/genirq-introduce-irq_chip_set_type_parent-helper.patch queue-4.1/arm-omap-wakeupgen-restore-the-irq_set_type-mechanism.patch