Re: [PATCH v5 2/5] tick: Add freeze timer events

[dbasehore .]

On Mon, Jul 17, 2017 at 11:40 PM, Thomas Gleixner <tglx@xxxxxxxxxxxxx> wrote:
> On Mon, 17 Jul 2017, dbasehore . wrote:
>> On Mon, Jul 17, 2017 at 6:33 PM, Rafael J. Wysocki <rafael@xxxxxxxxxx> wrote:
>> I could make a patch to try it out. I would probably add a flag to rtc
>> timers to indicate whether it wakes the system (default true). We
>> would have to add a sync with the rtc irq and the rtc irqwork. I would
>> probably add a rtc_timer_sync function that would flush the rtc irq
>> and flush the irqwork. I would call this after the freeze_ops sync
>> function since the sci irq needs to finish before syncing with the rtc
>> irq. Also, pm_wakeup_irq seems racy with the current implementation of
>> s2idle_loop since the RTC irq could be mistakenly set as pm_wakeup_irq
>> when something else actually triggered the full wakeup. Fortunately, I
>> don't think pm_wakeup_irq is used for anything except debugging, but
>> we might change that.
>
> There is another option which you might consider. We can reserve one of the
> HPET comparators for that purpose and have a special interrupt handler for
> it. Checking the HPET for expiry from the low level code should be trivial.
>

Does that handle setting up new timers properly or does the timer sync
code still need to be written?

> Thanks,
>
>         tglx
>
>