What command or where in Ubuntu can you check the speed that USB devices are trained? Not the capability of the USB device but the actual trained speed of the current link.
For example we I plug in a USB3.1 Gen2 (10Gbps) hub to my desktop but the signal integrity is bad (to much insertion loss from a long cable) the hub trains at USB3.1 Gen (5Gbps) instead of Gen2
You have to run lsusb -t to get full tree of USB hubs.
Below is the example from my USB 3.0 capable laptop:
$ lsusb -t
/: Bus 04.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/4p, 5000M
|__ Port 2: Dev 6, If 0, Class=Mass Storage, Driver=usb-storage, 5000M
/: Bus 03.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/4p, 480M
|__ Port 1: Dev 3, If 0, Class=Human Interface Device, Driver=usbhid, 12M
|__ Port 1: Dev 3, If 1, Class=Human Interface Device, Driver=usbhid, 12M
/: Bus 02.Port 1: Dev 1, Class=root_hub, Driver=ehci-pci/2p, 480M
|__ Port 1: Dev 2, If 0, Class=Hub, Driver=hub/6p, 480M
|__ Port 5: Dev 126, If 0, Class=Video, Driver=, 12M
|__ Port 5: Dev 126, If 1, Class=Video, Driver=, 12M
|__ Port 6: Dev 5, If 0, Class=Wireless, Driver=btusb, 12M
|__ Port 6: Dev 5, If 1, Class=Wireless, Driver=btusb, 12M
/: Bus 01.Port 1: Dev 1, Class=root_hub, Driver=ehci-pci/2p, 480M
|__ Port 1: Dev 2, If 0, Class=Hub, Driver=hub/6p, 480M
|__ Port 4: Dev 3, If 0, Class=Vendor Specific Class, Driver=rtsx_usb, 480M
Above you can see 5000M hub port with USB 3.0 device - USB 3.0 flash.
Also there are slower devices with 480M and 12M speeds.
