[mythtv-users] Waking up at a time different than specified
Douglas Peale
Douglas_Peale at Comcast.net
Fri May 8 19:03:44 UTC 2026
On 5/7/26 12:59, Douglas Peale via mythtv-users wrote:
> 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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>>> MythTV Forums:https://forum.mythtv.org
>>
>> $ 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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>> http://wiki.mythtv.org/Mailing_List_etiquette
>> MythTV Forums:https://forum.mythtv.org
>
> 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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I think I found the problem. Boot from RTC had somehow gotten disabled again. I'm not sure how this is happening. The only thing
I have modified in the bios since the last time this happened is allowing the system to boot from USB because I needed to
re-install Linux.
--
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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