linux-kernel - Re: [PATCH] time: Fix sleeptime injection for non-stop clocksource & persistent clock

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Date:   Tue, 29 May 2018 14:18:19 +0530
From:   Vinod Koul <vinod.koul@...aro.org>
To:     Mukesh Ojha <mojha@...eaurora.org>
Cc:     linux-arm-msm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] time: Fix sleeptime injection for non-stop clocksource &
 persistent clock

On 29-05-18, 13:45, 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' due to which we can see mismatch in time with
> system 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()
> 
> Change-Id: I98928761c98cec21a3033a55d3e10fb34138f38c

This does not belong in upstream please remove. I think checkpatch warns.

Also I see that you have sent to lkml and arm-msm mailing list, but have not
CCed any maintainers. Please run ./scripts/get_maintainer.pl to find who to send
patches to. Chances are it will get ignored...

> Signed-off-by: Mukesh Ojha <mojha@...eaurora.org>
> ---
>  kernel/time/timekeeping.c | 14 +++++++++-----
>  1 file changed, 9 insertions(+), 5 deletions(-)
> 
> diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
> index 427e33d..c022d82 100644
> --- a/kernel/time/timekeeping.c
> +++ b/kernel/time/timekeeping.c
> @@ -1511,9 +1511,6 @@ void __weak read_boot_clock64(struct timespec64 *ts)
>  	ts->tv_nsec = 0;
>  }
>  
> -/* Flag for if timekeeping_resume() has injected sleeptime */
> -static bool sleeptime_injected;
> -
>  /* Flag for if there is a persistent clock on this platform */
>  static bool persistent_clock_exists;
>  
> @@ -1611,7 +1608,14 @@ static void __timekeeping_inject_sleeptime(struct timekeeper *tk,
>   */
>  bool timekeeping_rtc_skipresume(void)
>  {
> -	return sleeptime_injected;
> +	struct timekeeper *tk = &tk_core.timekeeper;
> +	bool skip_rtc_resume = false;
> +
> +	skip_rtc_resume = ((tk->tkr_mono.clock->flags &
> +			CLOCK_SOURCE_SUSPEND_NONSTOP) ||
> +			(persistent_clock_exists)) ? true : false;
> +
> +	return skip_rtc_resume;
>  }
>  
>  /**
> @@ -1671,8 +1675,8 @@ void timekeeping_resume(void)
>  	unsigned long flags;
>  	struct timespec64 ts_new, ts_delta;
>  	cycle_t cycle_now, cycle_delta;
> +	bool sleeptime_injected = false;
>  
> -	sleeptime_injected = false;
>  	read_persistent_clock64(&ts_new);
>  
>  	clockevents_resume();
> -- 
> Qualcomm India Private Limited, on behalf of Qualcomm Innovation Center,
> Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
> 
> --
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-- 
~Vinod