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SubjectRe: [PATCH v2] time: Fix sleeptime injection for non-stop clocksource & persistent clock
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Any input on this ?

Thanks,
Mukesh
On 5/30/2018 5:14 PM, Mukesh Ojha wrote:
> Currently, for both non-stop clocksource and persistent clock
> there is a corner case, when a driver failed to go suspend mode.
> rtc_resume() injects the sleeptime as timekeeping_rtc_skipresume()
> returned 'false'(sleeptime_injected=false) due to which we can
> see mismatch in timestamps between system clock and other timers.
>
> Fix this by updating sleeptime_injected=true for both non-stop
> clocksource and persistent clock.
>
> Success case:
> ------------
> {sleeptime_injected=true}
> rtc_suspend() => timekeeping_suspend() => timekeeping_resume() =>
> rtc_resume()
>
> Failure case:
> ------------
> {failure in sleep path} {sleeptime_injected=false}
> rtc_suspend() => rtc_resume()
>
> Signed-off-by: Mukesh Ojha <mojha@codeaurora.org>
> ---
> Changes in v2:
> * Updated the commit text.
> * Removed extra variable and used the earlier static
> variable 'sleeptime_injected'.
>
> kernel/time/timekeeping.c | 11 +++++++++++
> 1 file changed, 11 insertions(+)
>
> diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
> index 49cbcee..2754c1b 100644
> --- a/kernel/time/timekeeping.c
> +++ b/kernel/time/timekeeping.c
> @@ -1610,6 +1610,17 @@ static void __timekeeping_inject_sleeptime(struct timekeeper *tk,
> */
> bool timekeeping_rtc_skipresume(void)
> {
> + struct timekeeper *tk = &tk_core.timekeeper;
> + /*
> + * This is to ensure that we don't end up injecting
> + * the sleeptime via rtc_resume() for non-stop clocksource
> + * when we fail to sleep.
> + */
> + if (!sleeptime_injected)
> + sleeptime_injected = ((tk->tkr_mono.clock->flags &
> + CLOCK_SOURCE_SUSPEND_NONSTOP) ||
> + (persistent_clock_exists)) ? true : false;
> +
> return sleeptime_injected;
> }
>

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