Legacy Kernel Caller preventing sleep mode

I have a problem with Windows 7 not sleeping.

PowerCfg -requests

says a "Legacy Kernel Caller" driver prevents the sleep mode. This is not very helpful or informative. How do I get more details about that object?

EDIT:

I found that

Powercfg -requestsoverride

is the best way of dealing with such misbehaving drivers and software.

The option -requestsoverride is not very well documented. MSDN doesn't mention NAME is case sensitive, and to remove a request from overrides list you give the option with blank REQUEST parameter.

majocha

Posted 2011-12-21T22:42:22.140

Reputation: 433

I'm sorry I'm still confused: what is the full command? I have the exact same "Legacy Kernel Caller" thing listed. I tried using powercfg /requestoverride driver Legacy Kernel Caller. It seems like it didn't do anything. – StormRyder – 2018-04-14T18:50:06.547

I added another suggest: powercfg -request – surfasb – 2011-12-22T05:58:22.977

That's the command I used initially :) – majocha – 2011-12-22T09:19:07.890

Answers

Thanks for all the suggestions!

Finally I narrowed down the problem simply by trial and error, disabling devices and rebooting. It was a TV card driver hung and not releasing the power request despite being no longer in use.

EDIT:

Unfortunately, the problem with TV card is intermittently recurring. Googling shows it's also quite common. I found that disallowing the driver from making power requests with

Powercfg -requestsoverride Driver "Legacy Kernel Caller" System

solves it.

"Legacy Kernel Caller" is translated on different Windows language versions. On my Polish system it says "Starszego typu obiekt wywołujący jądro".

majocha

Posted 2011-12-21T22:42:22.140

Reputation: 433

1When I run powercfg -requestsoverride Driver "Legacy Kernel Caller" System, where it succeeds, and then powercfg -requests, it still shows [DRIVER] Legacy Kernel Caller under SYSTEM: in the list of things preventing the computer from sleeping. So it doesn't work. – Neil – 2015-11-28T02:01:43.770

For me it worked, in terms of removing the entry. (Turned out that HipChat prevented sleep mode and not the PERFBOOST entry.) – Simon A. Eugster – 2016-03-02T14:01:36.263

I would still like to know how to determine which device is the culprit, without relying on just trial and error. – posfan12 – 2018-04-23T03:58:47.067

I set the config successfully, but I still cannot put my pc to sleep. //edit: Oh wow, 8 years later. Win 10 Pro. – Qwerty – 2019-02-17T04:00:59.100

1Thanks for adding the English translation - solved my issue too. – Praesagus – 2013-04-30T15:26:25.227

From the start menu, type in "Performance Information and Tools".

Click the Advanced Tools and click generate a System Health Report. It should point out legacy driver issues.

Edit:

Also try powercfg -request.

surfasb

Posted 2011-12-21T22:42:22.140

Reputation: 21 453

3Unfortunately, the report was not helpful, there are no device problems indicated. – majocha – 2011-12-22T02:03:26.893

about par, 50,000 pieces of info and the one piece of info you need you cant get. That is probably why I would look through the device list and GUESS and temporarily disable. I tried a powercfg -devicequery all_devices_verbose and get too much info, but it would be hard to weed through it all. Pour it into a spreadsheet, or search for an exact flag, but what is the flag? – Psycogeek – 2011-12-22T02:36:42.023

@Psycogeek: That's the wrong command to run. Try powercg -requests. That just shows the drivers that are keeping the system from sleeping. – surfasb – 2011-12-22T05:41:11.490

yes "requests" not "request" ? (not understanding that) . I was trying to find a way for the OP to discover possible items using the full list, which shows every devices power items. But is so thick with data it would take more info or more time to find one that might cause the error they got. – Psycogeek – 2011-12-22T08:40:10.870

In my case it was Spotfiy that misbehaved. People are going ballistic in their forums over this bug.

Solution: Quit spotify before putting computer to sleep/hibernate

I still question why on earth Windows allow a poorly programmed piece of software to override all power plan settings and create wake timers. Microsoft should take their share of the blame here.

edit: Seems like issue is closed 3 days ago so I guess we should expect a fix soon.

Nilzor

Posted 2011-12-21T22:42:22.140

Reputation: 3 881

-1

Did you install Windows 7 on a machine that was meant for a different OS? Ie, did you download/install Windows 7 drivers for your computer. I've seen this issue with other computers that were a bit dated back. Some had Win7 drivers available but the others were SoL. Also, check firmware updates on your BIOS/Motherboard as it could be an ACPI issue.

kobaltz

Posted 2011-12-21T22:42:22.140

Reputation: 14 361

1Ask questions in the comments section of the initial question. – Neil – 2015-11-28T02:02:33.000