Power management not working?

I have Windows 7 Home Premium x64 (Retail) installed on my desktop at home. So far I love it. I ran the RC prior to this and found it much, much better than I had expected.

Anyway, for some reason my computer is not suspending itself any more. It worked fine for the first week, turning "off" after about 30 minutes. Great feature, especially since I have a NAS for file and printer sharing now; I don't need to have my desktop on all the time anymore. This started happening yesterday. The only thing out of the ordinary that I have done is cancel an automatic AVG scan yesterday so I could play some games after work.

Could canceling this scan have triggered something? I went into the Power Management screen multiple times and reset the suspend time (it never changed from 30 minuites until I changed it to 25 and back to 30). I restarted the computer this morning, so I'm not sure if it's still happening; but has anyone heard of something like this?

As an update to this:

I ran powercrfg -events and powercfg -requests last night to try to determine where the hang up was, and apparently something is using my audio driver, preventing it from going to sleep properly.

I can put it to sleep via the start menu with no problems, it just won't do it automatically for some reason.

My next step is going to be to either find an updated driver that hopefully won't do this, or simply uninstall the driver and let Windows use its own driver. I've searched the net, and this seems to be a common issue with the SigmaTel HDAudio drivers.

liquidzoo said:

As an update to this:

I ran powercrfg -events and powercfg -requests last night to try to determine where the hang up was, and apparently something is using my audio driver, preventing it from going to sleep properly.

I can put it to sleep via the start menu with no problems, it just won't do it automatically for some reason.

My next step is going to be to either find an updated driver that hopefully won't do this, or simply uninstall the driver and let Windows use its own driver. I've searched the net, and this seems to be a common issue with the SigmaTel HDAudio drivers.

I had the same problem with my machine not going to sleep all of a sudden (After having worked fine before) I ran the powercfg -ENERGY, and it came up with a couple of things:-

System Availability Requests:System Required Request
The device or driver has made a request to prevent the system from automatically entering sleep.
Requesting Driver InstanceHDAUDIO\FUNC_01&VEN_10EC&DEV_0885&SUBSYS_1458A102&REV_1001\4&174ede36&0&0001Requesting Driver DeviceHigh Definition Audio Device

and the following on processor usage

CPU Utilization:Processor utilization is moderate
The average processor utilization during the trace was moderate. The system will consume less power when the average processor utilization is very low. Review processor utilization for individual processes to determine which applications and services contribute the most to total processor utilization.
Average Utilization (%)2.28


CPU Utilization:Individual process with significant processor utilization.
This process is responsible for a significant portion of the total processor utilization recorded during the trace.
Process Name audiodg.exe
PID 880
Average Utilization (%)1.08

Module Average Module Utilization (%)
\Device\HarddiskVolume1\Windows\System32\AudioEng.dll 0.81\SystemRoot\system32\ntoskrnl.exe 0.09
\Device\HarddiskVolume\Windows\System32\msvcrt.dll 0.06

Now when I checked at the back of the machine the one thing I had plugged in a week or so ago was a line input to record from a tape deck. Unplugged that, and now the machine goes to sleep on its own fine. Simply setting the mixer to mute for that channel wasn't enough.

Not sure whether this is related to an audio driver update as well which was applied, but that's what my issue turned out to be. Must be just enough mains hum being picked up on the line input to cause some processing which then disables the sleep of the machine.

Anyhow well worth checking.