[SOLVED] Where is my USB 2.0 port?

JASlinux · 12-27-2020, 05:09 AM

I have an old desktop with 4 physical USB 1.1 ports, but lsusb reports a 5th 2.0 port. The machine's physical appearance corresponds with the User's Guide:

Where or what could it possibly be?

Code:

▶—— USB DEVICES (lsusb) ——◀

Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 002 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 005 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub


▶—— USB DEVICES (lsusb -t) ——◀

Bus 05.Port 1: Device 1, Class=root_hub, Driver=ohci-pci/2p, 12Mbit/s
Bus 04.Port 1: Device 1, Class=root_hub, Driver=ohci-pci/3p, 12Mbit/s
Bus 03.Port 1: Device 1, Class=root_hub, Driver=uhci_hcd/2p, 12Mbit/s
Bus 02.Port 1: Device 1, Class=root_hub, Driver=uhci_hcd/2p, 12Mbit/s
Bus 01.Port 1: Device 1, Class=root_hub, Driver=ehci-pci/5p, 480Mbit/s

Bus 001 Device 001: 
 ID = 1d6b:0002 Linux Foundation 2.0 root hub
 USB Version = 2.00
 Manufacturer = Linux 4.4.95 ehci_hcd
 Product = EHCI Host Controller
 Serial Number = 0000:03:0d.2
 Class = Hub

berndbausch · 12-27-2020, 05:38 AM

I didn't know either, but was curious and searched the internet. The first result says

Quote:

The "root hub" is a phony device and represents the bus itself. It always has a device number of 1 on whatever bus it sits on. The "manufacturer" is always 1d6b, the "Linux Foundation," but so far as I can tell, that's merely to create a "root" for the tree's "branches"

I did wonder how a device could be manufactured by the Linux Foundation. The answer is obviously "it's a software-based device".

JASlinux · 12-27-2020, 06:33 AM

Quote:

Originally Posted by berndbausch

I didn't know either, but was curious and searched the internet. The first result says

I did wonder how a device could be manufactured by the Linux Foundation. The answer is obviously "it's a software-based device".

That's good sleuthing.

I found a PCI card on board with tape over it. That has to be it.

Now the question is about it working. If you don't need them for printers and input devices, one 2.0 device is more valuable than four 1.1s.

I think it was taped because it wasn't working.

computersavvy · 12-29-2020, 10:29 AM

PCI card? That is easily installed/removed. Why would someone tape over it unless needed for some other purpose.? Is something else plugged into that card somehow, or is it just a placeholder? Maybe the software did not support USB 2 when the machine was last used so to avoid confusion the user taped over the port.