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Subject: Re: [PATCH] powerpc/smp: Do not disable IPI interrupts during suspend
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From: Kumar Gala <galak@kernel.crashing.org>
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Date: Fri, 10 Aug 2012 07:40:19 -0500
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To: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: "linuxppc-dev@lists.ozlabs.org list" <linuxppc-dev@lists.ozlabs.org>,
 Zhao Chenhui <chenhui.zhao@freescale.com>,
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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:
>>>=20
>>>> 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.
>>>>=20
>>>> Signed-off-by: Zhao Chenhui <chenhui.zhao@freescale.com>
>>>> Signed-off-by: Li Yang <leoli@freescale.com>
>>>> ---
>>>> arch/powerpc/kernel/smp.c |    2 +-
>>>> 1 files changed, 1 insertions(+), 1 deletions(-)
>>>=20
>>> BenH,
>>>=20
>>> Can you ack?
>>=20
>> 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.
>>=20
>> Curiosity: didn't we use to disable all non-boot CPUs on suspend ?
>>=20
>> Cheers,
>> Ben.
>=20
> 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().
>=20
> -Chenhui

Benh, Ack?

- k=