Re: [RFC/PATCH] PM / Sleep: Timer quiesce in freeze state

From: Li, Aubrey
Date: Tue Oct 28 2014 - 04:03:10 EST


On 2014/10/27 15:44, Peter Zijlstra wrote:
> On Mon, Oct 27, 2014 at 02:27:27PM +0800, Li, Aubrey wrote:
>>>> +static void freezer_suspend_tk(int cpu)
>>>> {
>>>> + if (tick_do_timer_cpu != cpu)
>>>> + return;
>>>> +
>>>
>>> I had a note here that this might be broken for clocksource drivers that
>>> have suspend/resume methods. You seem to have 'lost' that note, is that
>>> because you found it isn't a problem?
>>>
>> I don't see it's a problem as long as we do not refer the clock source
>> before it resumes. But I think my testing didn't cover that case that
>> clock source drivers have suspend/resume methods. Can you please give
>> more details what do you worry about?
>
> I can't seem to recall :/ Maybe I conflated clocksource and clockevents
> and figured we'd need to run the clocksource suspend callback on each
> cpu.

Both clocksource and clockevents are not per-cpu device, why do we need
to run their suspend callback on *each* cpu?

Thanks,
-Aubrey

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