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 [off-list ref] know about it.

From 6d4affea7d5aa5ca5ff4c3e5fbf3ee16801cc527 Mon Sep 17 00:00:00 2001

From: Grygorii Strashko <grygorii.strashko@ti.com>
Date: Fri, 14 Aug 2015 15:20:25 +0300
Subject: genirq: Don't return ENOSYS in irq_chip_retrigger_hierarchy

From: Grygorii Strashko <grygorii.strashko@ti.com>

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 ]

Fixes: 85f08c17de26 ('genirq: Introduce helper functions...')
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Reviewed-by: Marc Zyngier <redacted>
Reviewed-by: Jiang Liu <redacted>
Cc: Sudeep Holla <redacted>
Cc: <redacted>
Cc: <redacted>
Cc: <redacted>
Cc: <redacted>
Cc: <redacted>
Cc: <tony@atomide.com>
Link: http://lkml.kernel.org/r/1439554830-19502-2-git-send-email-grygorii.strashko at ti.com
Signed-off-by: Thomas Gleixner <redacted>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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

--- a/kernel/irq/chip.c
+++ b/kernel/irq/chip.c

@@ -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