[mythtv-users] Waking up at a time different than specified

[Douglas Peale]

On 5/7/26 11:55, Douglas Peale via mythtv-users wrote:
> On 5/7/26 11:48, Roland Ernst wrote:
>>
>>
>> On Thu, May 7, 2026 at 7:49 PM Douglas Peale via mythtv-users <mythtv-users at mythtv.org> wrote:
>>
>>     I have my myth TV set up to shut off when it is idle, and nobody is using the computer.
>>
>>     It is setting the correct time to wake up, and shutting down, but it is waking up at a different time than specified.
>>
>>      From the backend log:
>>
>>     2026-05-06T23:32:16.416290-07:00 BlackBox mythbackend: mythbackend[17054]: N Scheduler scheduler.cpp:3429 (ShutdownServer)
>>     Running the command to set the next scheduled wakeup time :-#012#011#011#011#011sudo sh -c "/usr/bin/setwakeup.sh 1778201587"
>>     2026-05-06T23:32:16.416372-07:00 BlackBox mythbackend: mythbackend[17054]: N Scheduler scheduler.cpp:3460 (ShutdownServer)
>>     Running the command to shutdown this computer :-#012#011#011#011#011setsid /usr/bin/shutdown.sh
>>
>>
>>     the setwakeup.sh command is as follows:
>>
>>     #!/bin/bash
>>     #$1 is the first argument to the script. It is the time in seconds since 1970
>>     #this is defined in mythtv-setup with the time_t argument
>>
>>     LOG_FILE='/var/log/mythtv/hwclk.log'
>>
>>     #I don't know how to ask MythTV for this value, so it is duplicated here. This is ugly.
>>     #number of seconds before scheduled recording that computer should start booting.
>>     startbeforerecord=600
>>
>>     #Calculate time_t format time for next non MythTV event. Note that the user event time is hard coded!
>>     # This hard coded time must match the time of the event you schedule in cron.
>>
>>     currenttime=$(date "+%Y-%m-%d %H:%M:%S %s")
>>
>>     userevent=$(( $(date -d 3:00AM +%s) - startbeforerecord ))
>>
>>     (( userevent += ( userevent < $(date +%s) ) ? 24*60*60 : 0 )) # If event time has already passed, add 1 day
>>
>>     # Set wake time to the earliest of MythTVs wake time and userevent
>>     (( waketime = ( userevent < $1 ) ? userevent : $1 ))
>>
>>     echo $currenttime MythTV requested $1 UserEvent is $userevent Chosen time to wake is $waketime >> $LOG_FILE
>>
>>     #Does not seem to work anymore on Mint
>>     #echo 0 > /sys/class/rtc/rtc0/wakealarm      #this clears your alarm.
>>     #echo $waketime > /sys/class/rtc/rtc0/wakealarm  #this writes your alarm
>>
>>     #try this instead:
>>     rtcwake -m no -t $waketime >>$LOG_FILE
>>
>>
>>     The log file it writes is:
>>
>>     2026-05-06 23:32:16 1778135536 MythTV requested 1778201587 UserEvent is 1778147400 Chosen time to wake is 1778147400
>>     rtcwake: wakeup using /dev/rtc0 at Thu May  7 09:49:53 2026
>>
>>     Note that the time specified in the log is in GMT which would be 2:50AM local time (not sure why there is a a 7 second
>>     discrepancy).
>>
>>
>>     But the next entry in the backend log is:
>>
>>     2026-05-07T17:08:22.484022-07:00 BlackBox mythbackend: mythbackend[2214]: C thread_unknown mythcommandlineparser.cpp:2904
>>     (ConfigureLogging) mythbackend version: fixes/34 [v34.0+fixes.20240210.e3e165a1-0ubuntu6] www.mythtv.org
>>     <http://www.mythtv.org>
>>
>>     So the computer shut down, then woke up at 8 minutes after midnight even though it was told to wake up at 2:50 AM.
>>
>>
>>     My scripts appear to be working correctly, but the computter is waking up at the wrong time.
>>
>>     What am I missing?
>>
>>     -- 
>>     Note: the attached .asc file is a cryptographic signature that would allow you to verify that this message has not been
>>     modified from what was sent.
>>
>>
>>
>> Please post the output of `timedatectl`.
>>
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>
> $ timedatectl
>                Local time: Thu 2026-05-07 11:54:48 PDT
>            Universal time: Thu 2026-05-07 18:54:48 UTC
>                  RTC time: Thu 2026-05-07 18:54:41
>                 Time zone: America/Los_Angeles (PDT, -0700)
> System clock synchronized: yes
>               NTP service: active
>           RTC in local TZ: yes
>
> Warning: The system is configured to read the RTC time in the local time zone.
>          This mode cannot be fully supported. It will create various problems
>          with time zone changes and daylight saving time adjustments. The RTC
>          time is never updated, it relies on external facilities to maintain it.
>          If at all possible, use RTC in UTC by calling
>          'timedatectl set-local-rtc 0'.
>
> -- 
> Note: the attached .asc file is a cryptographic signature that would allow you to verify that this message has not been modified from what was sent.
>
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I just noticed the warning and ran the suggested command. We will see tonight if that changed anything.

-- 
Note: the attached .asc file is a cryptographic signature that would allow you to verify that this message has not been modified from what was sent.

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