On 4-2-2018 15:04, Paul wrote:
Fokke Nauta wrote:
Hi all,

Using a server in our LAN (W10 pro 64b). It is using a master-slave
mains power connector, which works by a USB cable. When the server is
on, the slave power connector is on, and from there the other pc's and
the switch and router get their mains power.
This works well, but when the server is down (switched off or in
hibernation), there is still +5 V on the USB connectors, causing the
slave mains supply to remain on.
Is there any chance to shut down the USB connectors as well when the
server is off or in hibernation mode?

Thanks beforehand.

Fokke

Maybe.

Modern motherboards, unfortunately, have no USBPWR 2x3 header
on the motherboard. Modern motherboards run the USB port from
+5VSB.

Older computers, each USB port had a jumper, and the jumper
selected +5V or +5VSB.

o----o === Jumper selects power source.
X X X The jumper position shown would
+5V Port +5VSB be the one you desire. +5V goes
PWR off when the computer sleeps, suitable
for tripping auxiliary equipment.

Modern motherboards don't have that option. They are permanently wired.
There is no jumper. Just copper traces on the PCB. This electrical
connection would be near (on one end of) the green Polyfuse. Since
all the USB ports use +5VSB, the power stays on during sleep. This
allows charging toys, or allows keyboard/mouse wakeup.

X----X
Port +5VSB
PWR

Only if the port has a downstream MOSFET switch, could the
+5VSB be turned off.

I notice that the Windows 10 power management tick boxes, look
different than the other OSes. The root hubs seem to have
power boxes, but not the devices themselves. Which implies
you don't have per-port control via Device Manager. Maybe your
tick boxes will look different ? Notice how my keyboard and mouse
have the box grayed out.

https://s9.postimg.org/av6lkak1b/win...ions_goofy.gif

Since I've seen what looks like the power going off, I assume
there's a way to do it. and there is a downstream MOSFET. However,
it isn't clear where that is located. It's not practical to be
doing that from the Southbridge, and the motherboard makers
hate to add stuff like that outside the Southbridge. After
all, they removed the USBPWR headers to save $0.05 per motherboard.

Paul

Hi Paul,

Thanks for your extensive info.
And thanks for the picture. I see the same options to power down the USB
hubs. But I don't know as to whether this is when the system is powered
up or in sleep mode. I'll have a look into this.

Fokke