linux-kernel - Re: [PATCH v5 3/6] genirq/PM: Introduce IRQCHIP_ENABLE_WAKEUP_ON

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Message-ID: <874koqxv6t.fsf@nanos.tec.linutronix.de>
Date:   Tue, 25 Aug 2020 23:38:34 +0200
From:   Thomas Gleixner <tglx@...utronix.de>
To:     Stephen Boyd <swboyd@...omium.org>,
        Maulik Shah <mkshah@...eaurora.org>,
        bjorn.andersson@...aro.org, evgreen@...omium.org,
        linus.walleij@...aro.org, maz@...nel.org, mka@...omium.org
Cc:     linux-kernel@...r.kernel.org, linux-arm-msm@...r.kernel.org,
        linux-gpio@...r.kernel.org, agross@...nel.org,
        jason@...edaemon.net, dianders@...omium.org, rnayak@...eaurora.org,
        ilina@...eaurora.org, lsrao@...eaurora.org,
        Maulik Shah <mkshah@...eaurora.org>
Subject: Re: [PATCH v5 3/6] genirq/PM: Introduce IRQCHIP_ENABLE_WAKEUP_ON_SUSPEND flag

On Tue, Aug 25 2020 at 03:12, Stephen Boyd wrote:
> Quoting Maulik Shah (2020-08-22 09:16:58)
>> diff --git a/kernel/irq/pm.c b/kernel/irq/pm.c
>> index c6c7e18..2cc800b 100644
>> --- a/kernel/irq/pm.c
>> +++ b/kernel/irq/pm.c
>> @@ -69,12 +69,17 @@ void irq_pm_remove_action(struct irq_desc *desc, struct irqaction *action)
>>  
>>  static bool suspend_device_irq(struct irq_desc *desc)
>>  {
>> +       unsigned long chipflags = irq_desc_get_chip(desc)->flags;
>> +
>>         if (!desc->action || irq_desc_is_chained(desc) ||
>>             desc->no_suspend_depth)
>>                 return false;
>>  
>>         if (irqd_is_wakeup_set(&desc->irq_data)) {
>>                 irqd_set(&desc->irq_data, IRQD_WAKEUP_ARMED);
>> +
>> +               if (chipflags & IRQCHIP_ENABLE_WAKEUP_ON_SUSPEND)
>> +                       irq_enable(desc);
>
> Where is the corresponding change to resume_irq()? Don't we need to
> disable an irq if it was disabled on suspend and forcibly enabled here?

That part was below the POC code I provided in the fine print:

 "plus the counterpart in the resume path. This also ensures that state is
  consistent."

Who reads the fine print? :)