linux-kernel - Re: [PATCH RESEND v1 2/5] drivers: pinctrl: msm: enable PDC interrupt only during suspend

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Date:   Mon, 20 Aug 2018 09:49:59 -0600
From:   Lina Iyer <ilina@...eaurora.org>
To:     Marc Zyngier <marc.zyngier@....com>
Cc:     bjorn.andersson@...aro.org, sboyd@...nel.org, evgreen@...omium.org,
        linus.walleij@...aro.org, rplsssn@...eaurora.org,
        linux-kernel@...r.kernel.org, linux-arm-msm@...r.kernel.org,
        rnayak@...eaurora.org, devicetree@...r.kernel.org,
        andy.gross@...aro.org, dianders@...omium.org
Subject: Re: [PATCH RESEND v1 2/5] drivers: pinctrl: msm: enable PDC
 interrupt only during suspend

On Mon, Aug 20 2018 at 09:34 -0600, Marc Zyngier wrote:
>On 20/08/18 16:26, Lina Iyer wrote:
>> On Sat, Aug 18 2018 at 07:13 -0600, Marc Zyngier wrote:
>>> Hi Lina,
>>>
>>> On Fri, 17 Aug 2018 20:10:23 +0100,
>>> Lina Iyer <ilina@...eaurora.org> wrote:
>
>[...]
>
>>>> @@ -920,6 +928,8 @@ static int msm_gpio_pdc_pin_request(struct irq_data *d)
>>>>  	}
>>>>
>>>>  	irq_set_handler_data(d->irq, irq_get_irq_data(irq));
>>>> +	irq_set_handler_data(irq, d);
>>>> +	irq_set_status_flags(irq, IRQ_DISABLE_UNLAZY);
>>>
>>> Could you explain what this is trying to do? I'm trying to understand
>>> this code, but this function isn't in 4.18...
>>>
>> Oh, I have been able to test only on 4.14 so far. The flag does seem to
>> exist at least, I didn't get a compiler error.
>>
>> I read this in kernel/irq/chip.c -
>>
>> If the interrupt chip does not implement the irq_disable callback,
>> a driver can disable the lazy approach for a particular irq line by
>> calling 'irq_set_status_flags(irq, IRQ_DISABLE_UNLAZY)'. This can
>> be used for devices which cannot disable the interrupt at the
>> device level under certain circumstances and have to use
>> disable_irq[_nosync] instead.
>>
>> And interpreted this as something that this would prevent 'relaxed'
>> disable. I am enabling and disabling the IRQ in suspend path, that I
>> thought this would help avoid issues caused by late disable. Am I
>> mistaken?
>
>Sorry, I wasn't clear enough. I'm talking about what you're trying to do
>in this particular function (msm_gpio_pdc_pin_request), which doesn't
>exist in 4.18. Short of having a bit of context, I can hardly review this.
>
Sorry, my patch generation during the resend is messed up. Seems like I
didn't send that patch out during the resend.

-- Lina