wake from sleep but not hibernation

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  1. apb
    Posts : 58
    win 7 64bit
    Thread Starter
       #31

    Megahertz said:
    Denis, how can it be possible to Task scheduler ( a OS service) wake up a computer that is off (No OS running or in memory) ?
    I believe this is how this works. When the computer is in hibernation, it is not completely off. For example, the real time clock has to keep running. There is enough memory available in firmware to record the next wakeup, so that's all it needs to know. The power drain is very small. On my fat desktop PC, the hibernate power consumption is spec'ed at 0.6 W.

    When the computer is turned "off", whether that is still the case might depend on the motherboard (real time clock still has to run, though); I'm not sure. Note that for a momentary-contact power switch to work, there has to be a source of voltage, so the machine cannot ever be 100% off, although that voltage can come from the cmos battery if the machine has one. Not sure if modern laptops bother with a separate cmos battery.

    --peter
      My Computers

  2. Try3's Avatar
    Posts : 7,470
    Windows 10 Home x64 Version 20H2 Build 19042.928
       #32

    Try3 said:
    apb,
    Task scheduler can wake the computer from hibernation just as well as it can wake the computer from sleep if mains power is available.
    Denis
    Megahertz said:
    Denis, how can it be possible to Task scheduler ( a OS service) wake up a computer that is off (No OS running or in memory) ?
    I haven't got the foggiest idea what you are talking about. My post concerned a computer that was hibernating not one that was off. Windows is perfectly capable of checking Task scheduler during hibernation.

    Denis
    Last edited by Try3; 2 Weeks Ago at 06:56.
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  3. Megahertz's Avatar
    Posts : 2,423
    Windows 7 HP 64 - Windows 10 Pro - Lubuntu
       #33

    Try3 said:
    I haven't got the foggiest idea what you are talking about. My post concerned a computer that was hibernating not one that was off. Windows is perfectly capable of checking Task scheduler during hibernation.

    Denis
    For what I know, hibernation is to save the data from memory on the drive and turn the computer off.

    Hibernation (computing) - Wikipedia
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  4. Try3's Avatar
    Posts : 7,470
    Windows 10 Home x64 Version 20H2 Build 19042.928
       #34

    Megahertz said:
    For what I know, hibernation is to save the data from memory on the drive and turn the computer off.
    The computer does not turn off.
    Hibernation <> Off

    Denis
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  5. apb
    Posts : 58
    win 7 64bit
    Thread Starter
       #35

    Although asking about the "off" state in a discussion about hibernation might indicate some misunderstanding, it's nevertheless I believe correct that the computer actually is "off" when hibernating, pretty much as off as it is when it is "off." The only significant difference is that when it reboots, the OS reloads the saved state of the system, although it may be that due to mission creep more functions stay enabled even in "hibernation" relative to "off," such as for example the network, to allow wake on LAN.

    For example, in many BIOSes one can schedule a time to power "on." I believe all these functionalities rely on a common mechanism: the real time clock and enough firmware active to initiate the power-on. For example: How to Make Your PC Automatically Turn On on a Schedule .

    Meanwhile, as I have found, if my laptop is hibernated when on battery, then scheduled tasks will not wake the computer even if it is plugged into the wall and wake timers on AC are on, but wake timers on battery are off. Whether that is an issue with the OS or with firmware I don't know, nor whether it is an intentional behavior.
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  6. Megahertz's Avatar
    Posts : 2,423
    Windows 7 HP 64 - Windows 10 Pro - Lubuntu
       #36

    From Hibernation (computing) - Wikipedia, the definition for hibernation is to save memory to a file and turn the computer OFF.
    On the other hand, stand by or sleep is to put the computer on a low state, turning off video, drives and other hardware peripherals.
    Win 10 created (once again) something that isn't one thing or the other but a mix of the two. The memory data is saved to a file but it doesn't shut down. It is on a suspension mode waiting for a trigger to restart, loading data into memory as a real hibernation does.
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  7. Try3's Avatar
    Posts : 7,470
    Windows 10 Home x64 Version 20H2 Build 19042.928
       #37

    Windows calls hibernation a low power state not an off state.
    Log - System
    Source - Power-Troubleshooter
    EventID - 1
    {You need to look at the Details tab to see the difference between records of resuming from sleep & hibernation - only resume from hibernation has non-zero values for the Hiber* entries.}

    MS says that hibernation is not off and that it consumes power. Shut down, sleep, or hibernate your PC - MSSupport

    I have been responding to this particular topic because post #29 doubted that the computer could respond to TS tasks during hibernation. It can respond to them.

    - - - - - - - - - - -

    Peter,

    Have you managed to make any progress with your lack of wake timers on battery?
    - My non-S0 Modern standby computers have had AC & DC wake timers enabled by default.
    - My only S0 Modern standby computer does not have them listed in Power options. I have not tried to change that.

    Denis
      My Computer


  8. apb
    Posts : 58
    win 7 64bit
    Thread Starter
       #38

    Try3 said:
    - - - - - - - - - - -

    Peter,

    Have you managed to make any progress with your lack of wake timers on battery?
    - My non-S0 Modern standby computers have had AC & DC wake timers enabled by default.
    - My only S0 Modern standby computer does not have them listed in Power options. I have not tried to change that.

    Denis
    The short answer is no, and I won't be pursuing it further, because I think I understand why it is not doing what I expect.

    Here is the longer answer:

    My laptop does not have the wake timers listed in power options by default. I enabled them being listed using the registry key

    HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Power\PowerSettings\238C9FA8-0AAD-41ED-83F4-97BE242C8F20\BD3B718A-0680-4D9D-8AB2-E1D2B4AC806D

    , as described in this tutorial:

    Add or Remove Allow wake timers to Power Options in Windows 10

    That made it convenient to check the state of what was enabled. That dialog showed that wake timers were turned off for battery, and on for AC.

    All the behavior I saw was consistent with that, except that going into hibernation on battery caused wake to fail later even though on AC power. I don't know if that is a bug or a feature, but it is certainly repeatable. I have not checked whether turning on wake timers when on battery would have different results.

    --peter
      My Computers


 
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