Question PC won't power down after installing PCI USB expansion card

Oct 12, 2019
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I have a PCI expension card with 5 USB 2.0 ports with VIA VT6212L chip that I'd like to use with my PC.

After installing the card into the free PCI slot the PC boots up perfectly. The USB ports on the card work as they should. However, the problem is when shutting down the PC. After Windows has shut down, the PC won't power off. The keyboard and mouse LEDs go off suggesting that the USB ports on the motherboard have been powered off, but the PSU fan, CPU fan and case fans keep running indefinitely. In order for the PC to power down completely, I have to hold the power button for several seconds.

Someone suggested I look at the wakeup settings in the BIOS, so I have messed around with them a bit. Normally, I keep the "Wakeup by USB" setting set to Enabled, so that I can wake the PC from sleep just by pressing a key on the keyboard. The interesting thing is, if I set "Wakeup by USB" to Disabled, the PC will power down properly also with the PCI card installed. The downside is that I am not able to wake the PC from sleep by touching the keyboard or mouse, so I don't consider this a solution.

It's like there is somehow an active USB device plugged into the card, constantly waking up/preventing the PC from powering down (even if all the USB ports on the card are empty).

Another interesting thing is that the "Wakeup by PCI" setting was already set to Disabled. Yet somehow the PCI card still seems to be waking up/preventing the PC from powering down.

Could anyone more knowledgeable help me out with this?

Motherboard: MSI H97M-E35
OS: Windows 10 Pro
PCI USB expansion card: https://www.ebay.com/itm/High-Speed-480Mbps-5-Port-USB-2-0-PCI-Hub-Card-Controller-Adaptor-Module-New/172182415876?ssPageName=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649
 

kaehligj

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Mar 15, 2018
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You need to have the wakeup on USB enabled - to boot the pcb from a usb device activity.
And then the USB hub will need constant power to detect any activity on USB inputs.

This will override the PCI boot disable, because of the usb power requirements.
Sort of an egg and hen problem you've got.

If the PC has dedicated PS2 keyboard input connector, this is to be preferred, as then you can utilize the "wake up by keyboard" setting in bios.
I recall from years back, that ps2-to-usb converters were around, if you only have usb keyboard for a ps2 input.
You may leave the mouse connected to the usb hub, as it will come on few seconds after boot.
 
Oct 12, 2019
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OK, so you're suggesting that because USB wakeup is enabled, the PCI USB expansion card needs to have constant power in order to detect activity on USB?

It sounds reasonable, but there are a couple of things that don't really make sense to me.

First, the same is also true for the motherboard. It also needs power in order to detect USB activity and wakeup. And before I installed the PCI card, the motherboard was able to stay powered like this even though the PC was otherwise shut down in sleep mode (all fans stop and the power light goes into slow blinking mode). Can't the motherboard also supply that tiny bit of power needed to the PCI card in sleep mode, with fans powered down?

Second, even if the PC does indeed have to be powered on in order for the PCI card to detect USB activity, how come this problem also occurs when I am trying to shut down the PC completely, not just putting it into sleep?
 

kaehligj

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Mar 15, 2018
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You are not quite right.

The USB hub on the PCI bus must have power to work.
It can not work without power.
This power it can only get from the PCI mobo connector, which is powered by the PC MOBO general on state power.

The built in feature from the keyboard connector is a different story, as this is controlled by the onboard device controller, which is powered separately and also controls the power on/off to the motherboard in general.

This controller also takes the power button and reset button input from your PC case.

hope this clarifies a bit on the function of your mobo ?
 
Oct 12, 2019
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OK, so the motherboard needs to be fully on in order to supply the PCI with any power, if I understood correctly. And if that's the case, this solution will never work the way I want it, because I want the PC to be able to under sleep but I also want it to be able to wakeup on activity from the keyboard or mouse. I don't use PS/2 connectors, I use the built-in USB ports on the motherboard. I guess the MB is also able to power these separately when in sleep.

Thank you for you explanation.

Still, I don't really understand why it's not just a problem when entering sleep, but also when shutting down the PC...
 

kaehligj

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Mar 15, 2018
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... I also want it to be able to wakeup on activity from the keyboard or mouse. I don't use PS/2 connectors, I use the built-in USB ports on the motherboard. I guess the MB is also able to power these separately when in sleep.
...
Yes that should be true. Try it and come back with the result. I really want to see you get it working :)
 

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