Win7 sleeps but immediately wakes up

Recently what I thought was a motherboard failure prompted me to replace my motherboard.  I went from an Asus P5N-T Deluxe to a P5N-D.  That's a slight downgrade but it was a good deal on Newegg.  Anyways, after installing the motherboard I noticed problems with the Windows 7 sleep mode.  As soon as the computer went into sleep mode, it would immediately wake back up.  It didn't do this with the previous board.  Luckily, there is a built-in command that can tell you more about why Windows wakes up from a sleep.  I found this post which helped out a lot.

To paraphrase, there is a command called powercfg that can tell you certain details about sleep.  powercfg -lastwake will indicate what was the last device to wake your machine.  Here is some sample output from that command:

C:\>powercfg -lastwake
Wake History Count - 1
Wake History [0]
  Wake Source Count - 1
  Wake Source [0]
    Type: Fixed Feature
    Power Button

In this case, I used the power button to wake the machine. Use powercfg -devicequery wake_armed to get a list of all the devices that could wake your system.  Combine that information with -lastwake and you know which device name to disable. Use powercfg -devicedisablewake <devicename> to disable a device. For some reason, all of my USB devices were causing the system to wake so I shut them off. I don't have too much problem with using the power button to wake the computer especially when the alternative is to have to shut it off entirely.

One thing I never found much information about is what the sleep states are. In the BIOS, there are two ACPI suspend types listed: S1 & S3.  This is backed up by what powercfg -a reports:

C:\Users\Dustin>powercfg -a
The following sleep states are available on this system: Standby ( S1 S3 ) Hibernate Hybrid Sleep
The following sleep states are not available on this system:
Standby (S2)
        The system firmware does not support this standby state.

Doing some fiddling with the BIOS settings, I noticed that S1 will let the computer sleep but the case fans are still running. My case fans are not connected to the motherboard. I still have to press the power button to wake. It's hard to tell what S3 does distinctly because as soon as it goes to S3 it wakes up again. I would doubt that my troubles are because the P5N-D does not support S2. Having had troubles with switching motherboards before, that seems a more likely explanation. The powercfg command provides a suitable workaround.

Comments (2)

  1. Michael Aulia says:

    Glad that the article has shed some light for you 🙂 It's a bit more frustrating when the command returns with a USB controller as there are many USB devices connected to the motherboard most of the time

  2. Tom says:

    Hi, I had similar problem, instant wake up after sleep, 'Wake History Count – 0', no devices with permissions to wake up, tried all power settings, but solution for my ASUS EeePC was disabling "Instant ON" – this is asus software. I simply installed it and disabled that feature and now my EeePC sleeps like it should.

    There is the soft:

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