linux-kernel - Re: [PATCH v2 2/6] genirq: fix irqchip_set_wake_parent if IRQCHIP_SKIP_SET

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Date:	Thu, 13 Aug 2015 15:58:59 +0300
From:	Grygorii Strashko <grygorii.strashko@...com>
To:	Marc Zyngier <marc.zyngier@....com>,
	"tglx@...utronix.de" <tglx@...utronix.de>,
	"tony@...mide.com" <tony@...mide.com>
CC:	"linux@....linux.org.uk" <linux@....linux.org.uk>,
	"nsekhar@...com" <nsekhar@...com>,
	"jason@...edaemon.net" <jason@...edaemon.net>,
	"balbi@...com" <balbi@...com>,
	"linux-omap@...r.kernel.org" <linux-omap@...r.kernel.org>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 2/6] genirq: fix irqchip_set_wake_parent if IRQCHIP_SKIP_SET_WAKE

On 08/13/2015 01:31 PM, Grygorii Strashko wrote:
> 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
>>> configuration:
>>> ARM GIC<-OMAP wakeupgen<-TI CBAR<-GPIO<-GPIO pcf857x<-gpio_key
>>>
>>> gpio_key is wakeup source
>>>
>>> Failure is reproduced during suspend/resume to RAM:
>>> suspend:
>>>   - gpio_keys_suspend
>>>     enable_irq_wake
>>>       + 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
>>>
>>> resume:
>>>   - 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@...com>
>>> ---
>>>   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?
> 

I can confirm, if I revert this patch, add IRQCHIP_SKIP_SET_WAKE to
the crossbar and remove irq_chip_set_wake_parent wakeups still works.
What do you prefer me to do: add additional patch for the crossbar,
drop/keep this patch?

-- 
regards,
-grygorii
--
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