linux-kernel - Re: [PATCH 2/2] pinctrl: single: remove misuse of IRQF_NO

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Date:	Thu, 3 Dec 2015 20:35:30 +0200
From:	Grygorii Strashko <grygorii.strashko@...com>
To:	Tony Lindgren <tony@...mide.com>,
	Linus Walleij <linus.walleij@...aro.org>
CC:	Sudeep Holla <sudeep.holla@....com>,
	"linux-gpio@...r.kernel.org" <linux-gpio@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	<linux-omap@...r.kernel.org>
Subject: Re: [PATCH 2/2] pinctrl: single: remove misuse of IRQF_NO_SUSPEND
 flag

On 12/03/2015 08:13 PM, Tony Lindgren wrote:
> * Linus Walleij <linus.walleij@...aro.org> [151201 06:07]:
>> On Fri, Nov 27, 2015 at 6:21 PM, Sudeep Holla <sudeep.holla@....com> wrote:
>>
>>> From: Sudeep Holla <Sudeep.Holla@....com>
>>>
>>> The IRQF_NO_SUSPEND flag is used to identify the interrupts that should
>>> be left enabled so as to allow them to work as expected during the
>>> suspend-resume cycle, but doesn't guarantee that it will wake the system
>>> from a suspended state, enable_irq_wake is recommended to be used for
>>> the wakeup.
>>>
>>> This patch removes the use of IRQF_NO_SUSPEND flags replacing it with
>>> irq_set_irq_wake instead.
>>>
>>> Cc: Linus Walleij <linus.walleij@...aro.org>
>>> Cc: linux-gpio@...r.kernel.org
>>> Signed-off-by: Sudeep Holla <sudeep.holla@....com>
>>
>> I need Tony's ACK on this as well.
> 
> At least on omaps, this controller is always powered and we never want to
> suspend it as it handles wake-up events for all the IO pins. And that
> usecase sounds exactly like what you're describing above.
> 
> I don't quite follow what your suggested alternative for an interrupt
> controller is?
> 
> At least we need to have the alternative patched in with this chage before
> just removing IRQF_NO_SUSPEND.
> 
> The enable_irq_wake is naturally used for the consumer drivers of this
> interrupt controller and actually mostly done automatically now with the
> dev_pm_set_dedicated_wake_irq.
> 

I think, this patch should not break our wake-up functionality.
It will just change the moment when pcs_irq_handler() will be called:

before this change:
- suspend_enter()
  ....
  - arch_suspend_enable_irqs();
    - ^ right here

after this change:
- suspend_enter()
  ....
  dpm_resume_noirq()
  - resume_device_irqs()
    ^ here

Correct? And as for me this is more safe.

-- 
regards,
-grygorii
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