Recently my desktop machine (dual boot windows 7 and ubuntu 11.04) started resuming from suspend mode at random times. This usually happens in the middle of the night, but it happened once while I was at work. I never had this problem in the past, it only recently started happening a week ago.

My question is, how can I go about debugging this?

I've reset the bios, power cycled the machine, and checked disabled wake-on-lan and the wake on alarm settings of my motherboard. I'm completely out of ideas.

Any help greatly appreciated, -Bill

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    Does it resume from suspend/standby in both Windows and Ubuntu? – iglvzx Feb 3 '12 at 2:44
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    And if just Windows, do you have any scheduled tasks defined? Also, do you have a hibernate rule, Ie, suspend for after x minutes, hibernate after y minutes, so it is coming out of suspend to hibernate and the hibernate is failing? – Paul Feb 3 '12 at 3:02
  • @iglvzx - So far it hasn't reboot when I put it into suspend mode from windows. Could this possible be related to a recent kernel update? – Bill Zimmerman Feb 3 '12 at 17:31

On the windows 7 side, check the "power properties" , "change advanced power settings", "Sleep" . "allow wake timers" , "disable".

One more bios item, the "start back up on power loss" (by whatever name they use). That switched on can restart the computer after a power loss. The assumption here is that it lost power , which may look like it came out of standby. power fluxes could possibly trigger a wake via a device but it would be rare.

As paul mentined there are a few things in task scheduler in windows 7 that can awaken the computer to do thier things, but usually would allow it to go back to sleep when done. Also other software that is allowed to be run at startup, that starts looking for updates. There are ways to insure that nothing can ever wake from standby, when it comes to software.

A mouse that moved a pixel, more than one time in my working with computers an optical mouse was just in the right spot on a poor surface for optical movement recognition, and it kept the computer from going into standby. Speaking of mices, cats , dogs , kids, a breeze, or even a heating duct that might trigger a wake event via the mouse or keyboard. Testing that can go as far as removing both temporarily.

In Windows again, the event log would be a most valuable tool. it should show any restarts, any wake events. If you knew what time it occured, you could just look based on time also.

In a command prompt , try this powercfg /Wake Timers I have no idea what it does, because I have none, there are other fun options for powercfg so be sure to try powercfg /?

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    Thanks for the great feedback. I've tried all of this so far, but it seems to only be happening in ubuntu. Any further ideas? – Bill Zimmerman Feb 4 '12 at 17:11
  • now you need an expert in ubuntu, i cant even spell it :-0 – Psycogeek Feb 4 '12 at 17:48

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