linux-kernel - Re: [Regression] "irqdomain: Don't set type when mapping an IRQ" breaks nexus7 gpio buttons

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Date:	Thu, 11 Aug 2016 12:45:18 +0100
From:	Marc Zyngier <marc.zyngier@....com>
To:	Jon Hunter <jonathanh@...dia.com>,
	Linus Walleij <linus.walleij@...aro.org>,
	John Stultz <john.stultz@...aro.org>
Cc:	Thomas Gleixner <tglx@...utronix.de>,
	lkml <linux-kernel@...r.kernel.org>,
	Bjorn Andersson <bjorn.andersson@...aro.org>
Subject: Re: [Regression] "irqdomain: Don't set type when mapping an IRQ"
 breaks nexus7 gpio buttons

On 11/08/16 10:47, Jon Hunter wrote:
> 
> On 11/08/16 09:37, Marc Zyngier wrote:
>> On 08/08/16 22:48, Linus Walleij wrote:
>>> On Sat, Aug 6, 2016 at 1:45 AM, John Stultz <john.stultz@...aro.org> wrote:
>>>
>>>> @@ -614,7 +615,11 @@ unsigned int irq_create_fwspec_mapping(struct
>>>> irq_fwspec *fwspec)
>>>>                  * it now and return the interrupt number.
>>>>                  */
>>>>                 if (irq_get_trigger_type(virq) == IRQ_TYPE_NONE) {
>>>> -                       irq_set_irq_type(virq, type);
>>>> +                       irq_data = irq_get_irq_data(virq);
>>>> +                       if (!irq_data)
>>>> +                               return 0;
>>>> +
>>>> +                       irqd_set_trigger_type(irq_data, type);
>>>>                         return virq;
>>>>                 }
>>>>
>>>> If I revert just that, it works again.
>>>
>>> This makes my platform work too.
>>> Tested-by: Linus Walleij <linus.walleij@...aro.org>
>>
>> Hmmm. I'm now booting your kernel on the APQ8060, and reverting this
>> hunk doesn't fix it for me. I'm confused...
>>
>> The interesting part is this:
>> 109:     100000          0   msmgpio  88 Level     (null)
> 
> 88 is the pm8058 parent interrupt and so I am surprised you would even
> see this in /proc/interrupts as it should be a chained interrupt, right?

That's because it repeatedly fires without a proper handler, and only
appears then.

> Are you seeing this with all the ethernet updates for the APQ8060 in
> Linus' branch? I am curious what you see with stock v4.8-rc1 and if
> interrupts work ok with the change I had proposed. Hard to tell if there
> is more than one issue here.

(mostly) stock v4.8-rc1 exhibits the same issue, and your fix doesn't
help this particular issue. Reverting your fix *and* applying the above
revert makes it work again. Which is just papering over the issue, as it
only does something when the interrupt is seen for a second time.

I must be missing something obvious...

	M.
-- 
Jazz is not dead. It just smells funny...