linux-kernel - Re: [RFC][PATCH 2/2] PM: Rework handling of interrupts during suspend-resume

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Message-ID: <d6200be20902251950l34d5968q4b553ce8305ebd4b@mail.gmail.com>
Date:	Wed, 25 Feb 2009 19:50:52 -0800
From:	Arve Hjønnevåg <arve@...roid.com>
To:	Linus Torvalds <torvalds@...ux-foundation.org>
Cc:	Ingo Molnar <mingo@...e.hu>, "Rafael J. Wysocki" <rjw@...k.pl>,
	"Eric W. Biederman" <ebiederm@...ssion.com>,
	LKML <linux-kernel@...r.kernel.org>,
	Benjamin Herrenschmidt <benh@...nel.crashing.org>,
	Jeremy Fitzhardinge <jeremy@...p.org>,
	pm list <linux-pm@...ts.linux-foundation.org>,
	Len Brown <lenb@...nel.org>,
	Jesse Barnes <jbarnes@...tuousgeek.org>,
	Thomas Gleixner <tglx@...utronix.de>
Subject: Re: [RFC][PATCH 2/2] PM: Rework handling of interrupts during 
	suspend-resume

On Wed, Feb 25, 2009 at 7:37 PM, Linus Torvalds
<torvalds@...ux-foundation.org> wrote:
>
>
> On Wed, 25 Feb 2009, Arve Hjønnevåg wrote:
>>
>> That would not work without wakelocks support, since the interrupt
>> could occur after suspend_late which is the last chance for the driver
>> to abort sleep. (The patch also breaks my current wakelock
>> implementation since I use a suspend_late hook to abort sleep, but
>> this should be easy to fix)
>
> Since this must be some very deep arch-specific thing anyway, just make
> the dang thing be a "sysdev". At that point, its "suspend" function gets
> called way later (at which point CPU interrupts are off).

Wakelocks can use a sysdev, but I don't think a keyboard driver should
be a sysdev.

>
>> > Hm, if that solves the problem then it would be nice to have a
>> > new IRQF_NO_SUSPEND flag for it, in addition to IRQF_TIMER:
>>
>> I think the right fix is for any interrupt that has IRQ_WAKEUP set to
>> abort suspend if it is pending. I don't know if anyone relies on these
>> interrupts being dropped now though.
>
> We could add something like that, but quite frankly, I'd hate to unless
> there is some seriously common case. If it's just an oddball hacky special
> case, it's easier to just say "hey, you have that crazy system device, you
> handle it yourself".

I don't think this is a oddball case. It is very common to connect
keys or keypads to gpios. If these keys are wakeup keys, it is not OK
to loose interrupts during the suspend phase.

-- 
Arve Hjønnevåg
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