Re: [PATCH v2 2/6] genirq: fix irqchip_set_wake_parent if IRQCHIP_SKIP_SET_WAKE

From: Grygorii Strashko
Date: Thu Aug 13 2015 - 06:31:54 EST

On 08/13/2015 01:01 PM, Marc Zyngier wrote:
On 12/08/15 18:45, Grygorii Strashko wrote:
The irqchip_set_wake_parent should not fail if IRQ chip
specifies IRQCHIP_SKIP_SET_WAKE. Otherwise, IRQ wakeup
configuration can't be propagated properly through IRQ
domains hierarchy.

In case of TI OMAP DRA7 the issue reproduced with following
ARM GIC<-OMAP wakeupgen<-TI CBAR<-GPIO<-GPIO pcf857x<-gpio_key

gpio_key is wakeup source

Failure is reproduced during suspend/resume to RAM:
- gpio_keys_suspend
+ pcf857x_irq_set_wake
+ omap_gpio_wake_enable
+ TI CBAR irq_chip_set_wake_parent
+ OMAP wakeupgen has no .irq_set_wake()

Most importantly, wakeupgen has IRQCHIP_SKIP_SET_WAKE set.

and -ENOSYS will be returned

- gpio_keys_resume
+ disable_irq_wake
+ irq_set_irq_wake
+ WARN(1, "Unbalanced IRQ %d wake disable\n", irq);

Fixes: 08b55e2a9208 ('genirq: Add irqchip_set_wake_parent')
Signed-off-by: Grygorii Strashko <grygorii.strashko@xxxxxx>
kernel/irq/chip.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c
index 6de638b..bdb1b9d 100644
--- a/kernel/irq/chip.c
+++ b/kernel/irq/chip.c
@@ -1024,6 +1024,10 @@ int irq_chip_set_vcpu_affinity_parent(struct irq_data *data, void *vcpu_info)
int irq_chip_set_wake_parent(struct irq_data *data, unsigned int on)
data = data->parent_data;
+ if (irq_data_get_irq_chip(data)->flags & IRQCHIP_SKIP_SET_WAKE)
+ return 0;
if (data->chip->irq_set_wake)
return data->chip->irq_set_wake(data, on);

We have a more general issue with chip flags, and how they combine
within a stack of irqchips.

Indeed. Problem looks similar to IRQCHIP_MASK_ON_SUSPEND flag usage.

What if you remove the irq_chip_set_wake_parent from the crossbar
driver, and instead set IRQCHIP_SKIP_SET_WAKE?

I've thought about this and it should work for me.
One question - what if crossbar will be not the last one in
IRQ domains hierarchy?

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