Messages in this thread | | | Subject | Re: [PATCH RESEND] time: Fix sleeptime injection for non-stop clocksource & persistent clock | From | Mukesh Ojha <> | Date | Wed, 30 May 2018 15:57:02 +0530 |
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Hi John,
On 5/30/2018 7:50 AM, John Stultz wrote: > On Tue, May 29, 2018 at 2:49 AM, Mukesh Ojha <mojha@codeaurora.org> 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' due to which we can see mismatch in time between >> system clock and other timers. >> >> 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> > I'm not sure this patch makes sense yet (since I don't really see how > its used
In a system where both non-stop clocksource and rtc exist
Timestamp mismatch seen between a (Gyro)timer based on non-stop clocksource and system clock after attempting a sleep. Here, System clock timestamps increase by some millisecond as compare to other timer.
And we see this is possible only when timekeeping_resume() has not been called which is keeping sleeptime_injected to its default value(false). So, the call to timekeeping_rtc_skipresume() in rtc_resume() is false and thats ends up in sleeptime injection via rtc_resume().
When timekeeping_resume() has not been called means one of the driver failed during suspend in syscore_suspend() in kernel/power/suspend.c .
So if we let rtc inject the sleeptime here, we would see the timestamp increase in case of system clock.
> - mind cc'ing me on the patch that makes use of this?) > > And more problematic, the patch doesn't seem to apply to mainline. > Could you respin and resend?
Will spin the patch again with some minor code change.
Thanks, Mukesh
> > thanks > -john
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