linux-kernel - Re: [PATCH] PM: suspend_device_irqs(): don't disable wakeup IRQs

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Date:	Thu, 7 May 2009 10:28:16 +0900
From:	Kim Kyuwon <chammoru@...il.com>
To:	Arve Hjønnevåg <arve@...roid.com>
Cc:	Kevin Hilman <khilman@...prootsystems.com>,
	"Rafael J. Wysocki" <rjw@...k.pl>,
	Andrew Morton <akpm@...ux-foundation.org>,
	linux-pm@...ts.linux-foundation.org, linux-kernel@...r.kernel.org,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Ingo Molnar <mingo@...e.hu>
Subject: Re: [PATCH] PM: suspend_device_irqs(): don't disable wakeup IRQs

2009/5/7 Arve Hjønnevåg <arve@...roid.com>:
> On Wed, May 6, 2009 at 5:16 PM, Kevin Hilman
> <khilman@...prootsystems.com> wrote:
>> "Rafael J. Wysocki" <rjw@...k.pl> writes:
>>
>>> On Wednesday 06 May 2009, Kevin Hilman wrote:
>>>> Kevin Hilman <khilman@...prootsystems.com> writes:
>
>> There is at least one problem with that which is why Kyuwon Kim added
>> the ->disable hook to OMAP's irq_chip.  The problem is with drivers
>> that call disable_irq() in their suspend hook, usually done to prevent
>> the device from waking the system since on OMAP, any IRQ can be
>> configured to wake the system.
>>
>
> This does not sound correct. disable_irq_wake should be used for this.
> A driver may need to mask its interrupt before suspending but this
> should not also disable it as a wakeup source.

I wish I could use disable_irq_wake(), but it doesn't work in OMAP.

>> If a driver's suspend hook calls disable_irq() and the system is
>> suspended before the lazy disable happens in the next handler, then
>> the system will be suspended with that device's IRQ still enabled.
>> Without an irq_chip->disable hook, that will result in that device IRQ
>> waking up the system if it fires.
>
> The platform suspend code needs to write the wakeup mask into
> interrupt controller the before entering suspend.
>

ditto

> --
> Arve Hjønnevåg
> --
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-- 
Kyuwon (규원)
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