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    SubjectRe: [RFC/PATCH] PM / Sleep: Timer quiesce in freeze state
    On 2014/10/28 16:25, Peter Zijlstra wrote:
    > On Tue, Oct 28, 2014 at 03:52:17PM +0800, Li, Aubrey wrote:
    >
    >> Both clocksource and clockevents are not per-cpu device, why do we need
    >> to run their suspend callback on *each* cpu?
    >
    > Uhm, you mean to say we don't use per-cpu timer lists and per-cpu timer
    > hardware for clockevents then?
    >

    From OS level, currently tick device is per-cpu implementation while
    clocksource and clockevent devices are global device.

    We already stop tick by clockevents_notify(suspend) on each cpu, that
    addresses per-cpu timer list.

    And, we already call clocksource_suspend() and clockevents_suspend() in
    timekeeping_suspend() on the tick timer CPU. Yes, we didn't suspend
    per-cpu timer hardware on x86 because x86 does not have lapic timer
    suspend implementation. If we need to implement this, I think we can do
    the cross-CPU calls in clocksource/clockevents suspend(), but I didn't
    see any necessary we need to do this now.

    so, I think we are okay now, :)

    Thanks,
    -Aubrey


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