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

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Date:   Tue, 29 May 2018 15:09:06 +0530
From:   Mukesh Ojha <mojha@...eaurora.org>
To:     Vinod Koul <vinod.koul@...aro.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 5/29/2018 2:18 PM, Vinod Koul wrote:
> 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...

Thanks Vinod.
Will resend it after including maintainers.

-Mukesh
>
>> 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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