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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: Thu, 13 Sep 2012 13:16:51 -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 10, 2012, at 7:40 AM, Kumar Gala wrote:

>=20
> On Aug 2, 2012, at 5:04 AM, Zhao Chenhui wrote:
>=20
>> 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
>=20
> Benh, Ack?

Ben?

- k=