[GitHub] [incubator-nuttx] xiaoxiang781216 edited a comment on pull request #2625: Add time ticket related APIs to support hot sleep function

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xiaoxiang781216 edited a comment on pull request #2625:
URL: https://github.com/apache/incubator-nuttx/pull/2625#issuecomment-759443692


   > > > @xiaoxiang781216 could you take a look here please.
   > > 
   > > 
   > > Sorry, I thought this PR is for esp32 specific. So this patch want to sync the system time after wake up from RTC timer?
   > 
   > Hi @xiaoxiang781216 Yes, after entering auto-sleep(pm standby mode), the system clock interruption will stop, when exiting auto-sleep, the idletime tick obtained through watchdog monitoring (by calling wd_getidletime) will be inaccurate, so after exiting auto-sleep, the obtained system tick needs to be compensated (by calling wd_setsleepticks).
   
   But, the compensation isn't completed there are other places depend on the correct timing. At least:
   1. systime need to update
   2. sched::timeslice need to update
   2. Many field in sporadic_s need to update
   
   To sync the timing information, the better method is:
   1. Call nxsched_process_timer with enough times after wakeup for fixed tick mode
   2. up_timer_gettime return the compensated time for tickless mode
   
   The above method can ensure all timing related component get updated correctly.
   One improvement, we can change nxsched_process_timer prototype to accept the elasped ticks:
   void nxsched_process_timer(uint32_t ticks);


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