Re: [PATCH v1 4/5] gpio: max77620: Don't handle disabled interrupts

[Dmitry Osipenko]

08.07.2020 13:11, Andy Shevchenko ÐÐÑÐÑ:
> On Wed, Jul 8, 2020 at 12:19 PM Dmitry Osipenko <digetx@xxxxxxxxx> wrote:
>> 08.07.2020 11:46, Andy Shevchenko ÐÐÑÐÑ:
>>> On Wed, Jul 8, 2020 at 11:29 AM Dmitry Osipenko <digetx@xxxxxxxxx> wrote:
>>>>
>>>> Check whether GPIO IRQ is enabled before proceeding with handling the
>>>> interrupt request. The interrupt handler now returns IRQ_NONE if none
>>>> of interrupts were handled, which is usually a sign of a problem.
>>>
>>> ...
>>>
>>>> -       pending = value;
>>>> +       pending = value & gpio->irq_enb_mask;
>>>
>>>> +       if (!pending)
>>>> +               return IRQ_NONE;
>>>
>>> for_each_set_bit() should take care of it, no?
>>
>> Do you mean that the handle_nested_irq() takes care of handling
>> unrequested interrupts? Actually, looks like it cares. Alright, I'll
>> drop this patch since it should be unnecessary. Thank you for the comment!
> 
> I think it's still good to have reduced IRQs to handle by dropping not
> enabled ones, my comment was about the case when pending == 0. Sorry
> if it was unclear.

It should be unnecessary since we now see that the handle_nested_irq()
checks whether interrupt was requested and if it wasn't, then particular
GPIO interrupt will be treated as spurious [1]. The pending == 0
condition is an extreme case, I don't think that there is a need to
optimize it without any good reason.

[1] https://elixir.bootlin.com/linux/v5.8-rc3/source/kernel/irq/chip.c#L485

Hence it should be better to drop this patch.