dmesg -> lsusb -t

dmesg -> lsusb -t

[James Lockie]

$ sudo lsusb -t
/: Bus 04.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/4p, 5000M
    |__ Port 1: Dev 2, If 0, Class=Mass Storage, Driver=usb-storage, 5000M
/: Bus 03.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/4p, 480M
    |__ Port 2: Dev 3, If 0, Class=Vendor Specific Class, Driver=, 480M
    |__ Port 4: Dev 4, If 0, Class=Human Interface Device, Driver=usbfs, 1.5M
/: Bus 02.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/4p, 10000M
    |__ Port 2: Dev 3, If 0, Class=Mass Storage, Driver=uas, 5000M

$ dmesg
[42540.188430] usb 2-2: new SuperSpeed Gen 1 USB device number 3 using xhci_hcd

How is 'usb 2-2' mapped to lsusb?
I'm guessing it is the last entry from lsusb?

If it was a Gen 2 USB device it could run at 10000M?

Why is the first line of lsusb only 5000M?

Re: dmesg -> lsusb -t

[Alan Stern]

On Mon, 10 Feb 2020, James Lockie wrote:

> 
> $ sudo lsusb -t
> /: Bus 04.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/4p, 5000M
>     |__ Port 1: Dev 2, If 0, Class=Mass Storage, Driver=usb-storage, 5000M
> /: Bus 03.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/4p, 480M
>     |__ Port 2: Dev 3, If 0, Class=Vendor Specific Class, Driver=, 480M
>     |__ Port 4: Dev 4, If 0, Class=Human Interface Device, Driver=usbfs, 1.5M
> /: Bus 02.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/4p, 10000M
>     |__ Port 2: Dev 3, If 0, Class=Mass Storage, Driver=uas, 5000M
> 
> $ dmesg
> [42540.188430] usb 2-2: new SuperSpeed Gen 1 USB device number 3 using xhci_hcd
> 
> How is 'usb 2-2' mapped to lsusb?

It maps to the child entry below Bus 02 marked with Port 2.  In
addition, the dmesg line indicates that it maps to an entry with Dev 3.

> I'm guessing it is the last entry from lsusb?

Yes; that's the one which satisfies the mapping criteria.

> If it was a Gen 2 USB device it could run at 10000M?

Yes, assuming it was connected to a Gen 2 controller.

> Why is the first line of lsusb only 5000M?

Because that particular xHCI host controller is only Gen 1.

Alan Stern