Question USB 2.0 ports showing up under 3.0 controller ?

Feb 18, 2021
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I have an Asus Z97-K mobo that has USB 3.0 and USB 2.0 ports. I started getting errors in Windows 10 about running out of USB resources, and in troubleshooting this, I have discovered that all of the ports are somehow showing up (from Windows' perspective, anyway) as connected to the USB 3.0 controller. This is causing me to run out of endpoints. I've verified that these are the proper USB ports by verifying where the leads (and hard ports) are on the motherboard compared to the mobo's manual. Anyone ever seen this and know how to resolve it?
 

Colif

Win 10 Master
Moderator
I can't look on my Z97 motherboard right now but I think that is how it works now, if I look at my current PC, which has 4 USB 2 ports on the back, all of the USB items under USB controllers area of Device manager are all linked to USB 3 Extensible Host controllers, they are all connected to USB 3 even if they aren't themselves. I assume it is able to emulate USB2.

For instance, in top shot I highlighted Generic USB Hub which I would have to guess is USB 2, I then clicked View & changed it to Devices by connection and it shows in bottom shot that they all under USB 3 extensible Host Controller.


So that is normal, and not source of any problems you may have.

  1. Try using regular USB 2.0 ports instead of 3.0.
  2. Try using a docking station or USB Hub with its own power source so that it does not draws the power from Computer.
  3. Disabling the XHCI Mode Option from BIOS setting.
https://answers.microsoft.com/en-us/windows/forum/all/not-enough-usb-controller-resources-windows-10/b7dbbdda-a4b3-4c9b-96b5-131ea579afed?auth=1
 
Last edited:
Feb 18, 2021
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Actually, the devices plugged into a USB 2.0 port should be accounted for under the USB 2.0 controller and hub, not the USB 3.0 controller and hub. Endpoints on a 2.0 controller should not be counting towards the much lower endpoint limit in USB 3.0 - in fact, that's one reason to move devices from USB 3.0 to USB 2.0 ports - to lower the USB 3.0 resources used by slower devices.

Case in point: The smartcard reader highlighted here is connected to a USB 2.0 port (black connector, located adjacent to the Ethernet port, and clearly labeled as USB 2.0 in the Z97 manual). Frankly, it doesn't matter if it is plugged into that port or one of the ports connected to the headers connected to the USB 2.0 port connectors on the motherboard, the effect is the same. If I have this connected and try to connect a USB 3.0 hard disk to a USB 3.0 port, it will say that it is out of USB resources. If I unplug the smartcard reader first, the drive connects with no issue. Same with a USB SD card reader, etc.

 

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