Re: [PATCH] update clocksource raw_time in timekeeping_suspend

[ye janboe <janboe.ye@gmail.com>]

Thanks, Yong Zhang

But I do not think so. From the comments in commit
2d42244ae71d6c7b0884b5664cf2eda30fb2ae68, MONOTONIC_RAW want to give
users access to purely hardware based time.


2009/9/9 Yong Zhang <yong.zhang0@gmail.com>:
> On Wed, Sep 9, 2009 at 3:35 PM, ye janboe<janboe.ye@gmail.com> wrote:
>> after resume from suspend, raw_time is not updated in
>> timekeeping_suspend. CLOCK_MONOTONIC_RAW could not get the real hw
>> time.
>
> It seems that this is not a bug. The design of CLOCK_MONOTONIC_RAW doesn't
> say it will reflect the real hw time. It's just monotonic time which
> is unpoisoned by
> ntp.
>
> Cheers,
> Yong
>
>> This patch fix this issue.
>>
>> Signed-off-by: janboe <janboe.ye@gmail.com>
>> ---
>>  kernel/time/timekeeping.c |    6 ++++++
>>  1 files changed, 6 insertions(+), 0 deletions(-)
>>
>> diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
>> index e8c77d9..8420b85 100644
>> --- a/kernel/time/timekeeping.c
>> +++ b/kernel/time/timekeeping.c
>> @@ -331,6 +331,8 @@ static unsigned long timekeeping_suspend_time;
>>  static int timekeeping_resume(struct sys_device *dev)
>>  {
>>        unsigned long flags;
>> +       s64 nsec;
>> +       cycle_t last_cycle, cycle_delta;
>>        unsigned long now = read_persistent_clock();
>>
>>        clocksource_resume();
>> @@ -346,8 +348,12 @@ static int timekeeping_resume(struct sys_device *dev)
>>        }
>>        update_xtime_cache(0);
>>        /* re-base the last cycle value */
>> +       last_cycle = clock->cycle_last;
>>        clock->cycle_last = 0;
>>        clock->cycle_last = clocksource_read(clock);
>> +       cycle_delta = clock->cycle_last - last_cycle;
>> +       nsec = cyc2ns(clock, cycle_delta);
>> +       timespec_add_ns(&clock->raw_time, nsec);
>>        clock->error = 0;
>>        timekeeping_suspended = 0;
>>        write_sequnlock_irqrestore(&xtime_lock, flags);
>> --
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>