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Old February 12th 19, 03:16 AM posted to alt.comp.os.windows-10
Paul[_32_]
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Posts: 11,873
Default powercfg /a from a virtual machine

T wrote:
Hi All,

This is almost off topic, but I thought you guys would enjoy looking
at a "powercfg /a" on a qemu-kvm Windows 10 Pro virtual machine:


C:\WINDOWS\system32powercfg /a
The following sleep states are not available on this system:
Standby (S1)
The system firmware does not support this standby state.

Standby (S2)
The system firmware does not support this standby state.

Standby (S3)
The system firmware does not support this standby state.

Hibernate
The system firmware does not support hibernation.

Standby (S0 Low Power Idle)
The system firmware does not support this standby state.

Hybrid Sleep
Standby (S3) is not available.
Hibernation is not available.

Fast Startup
Hibernation is not available.


Chuckle!
-T


You can refrigerate a VM (Save State), which is why
it doesn't emulate all sorts of stuff.

The virtual machine is an application, and when it
suspends, the Host gets to use some power states.
If the virtual machine isn't doing something, the
host should be using its power-saving states as a
consequence.

And just to be clear, VMs present a "facade". They only
paint in enough details to barely allow a Guest OS to run.
This isn't a "forensic quality" environment, intended to
fool somebody. It's full of missed opportunities.

For example, the UEFI implementation inside VirtualBox is
"broken". You should not try to debug GPT/UEFI setups
via VirtualBox. If debugging such configs, you have
to install on "real" hardware, as the motherboard companies
pay money for "good" UEFI implementations. The MBR implementation
on the other hand, is good enough for the job, and many
little problems can be studied with the BIOS support
provided in VirtualBox.

Sometimes, it's trivial stuff. Like the BIOS counting
cores from "1", when the OS expects cores to be counted
from "0". Or the fake SoundBlaster is showing the wrong
"fake" checksum for some firmware or something, and the
sound driver in the Guest OS gets all bent out of shape
and turns off sound. It's like a house that had
student painters paint it during the summer months.
Little gaps here and there.

Paul
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