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

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

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
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/