linux-kernel - Re: [PATCH] powerpc/smp: Do not disable IPI interrupts during suspend

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Date:	Fri, 10 Aug 2012 07:40:19 -0500
From:	Kumar Gala <galak@...nel.crashing.org>
To:	Benjamin Herrenschmidt <benh@...nel.crashing.org>
Cc:	Zhao Chenhui <chenhui.zhao@...escale.com>,
	"linuxppc-dev@...ts.ozlabs.org list" <linuxppc-dev@...ts.ozlabs.org>,
	"linux-kernel@...r.kernel.org list" <linux-kernel@...r.kernel.org>,
	Li Yang <leoli@...escale.com>
Subject: Re: [PATCH] powerpc/smp: Do not disable IPI interrupts during suspend


On Aug 2, 2012, at 5:04 AM, Zhao Chenhui wrote:

> On Sat, Jul 28, 2012 at 08:20:31AM +1000, Benjamin Herrenschmidt wrote:
>> On Fri, 2012-07-27 at 16:58 -0500, Kumar Gala wrote:
>>> On Jul 20, 2012, at 7:47 AM, Zhao Chenhui wrote:
>>> 
>>>> During suspend, all interrupts including IPI will be disabled. In this case,
>>>> the suspend process will hang in SMP. To prevent this, pass the flag
>>>> IRQF_NO_SUSPEND when requesting IPI irq.
>>>> 
>>>> Signed-off-by: Zhao Chenhui <chenhui.zhao@...escale.com>
>>>> Signed-off-by: Li Yang <leoli@...escale.com>
>>>> ---
>>>> arch/powerpc/kernel/smp.c |    2 +-
>>>> 1 files changed, 1 insertions(+), 1 deletions(-)
>>> 
>>> BenH,
>>> 
>>> Can you ack?
>> 
>> No I'll merge it but not until it's been in next for a bit unless you
>> have some strong emergency there, it's on my mental list of things to
>> shovel into next after rc1.
>> 
>> Curiosity: didn't we use to disable all non-boot CPUs on suspend ?
>> 
>> Cheers,
>> Ben.
> 
> Yes, we disabled all non-boot CPUs on suspend by calling disable_nonboot_cpus().
> The disable_nonboot_cpus() needs IPIs to work. But prior to
> calling disable_nonboot_cpus(), the IPIs are disabled in dpm_suspend_noirq().
> 
> -Chenhui

Benh, Ack?

- k--
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