Re: device present in lsusb, disappears in lsusb -t

[Greg KH <gregkh@linuxfoundation.org>]

On Fri, Sep 15, 2023 at 08:16:18PM -0400, Douglas Gilbert wrote:
> The device in question is this one:
>   Bus 005 Device 015: ID 0483:572b STMicroelectronics STEVAL-USBC2DP Type-C
> to DisplayPort adapter. It is a USB-C alternate mode device (so tbtadm does
> not
> report it).
> 
> That adapter is connected to a screen (and working) and to a USB-C port on
> a Lenovo TB3 dock [40AN] which in turn is connected to a Thinkpad X13 Gen3's
> USB-C port. The Thinkpad is running lk 6.6.0-rc1 with "lsusb (usbutils) 014".
> 
> The strange thing is that this device is nowhere to be found in the output
> of "lsusb -t". The lsusb manpage describes the '-t' option as: "Tells
> lsusb to dump the physical USB device hierarchy as a tree." So is 'physical'
> a weasel word in this context, or is there a bug in the '-t' option, or is
> there some other explanation?

A number of 'lsusb -t' issues were fixed in the 015 release of usbutils,
so maybe update?

that being said, the -t option is a totally different codepath in the
tool, and shows different things overall.  -t shows the drivers that are
bound to the different interfaces, which means that a single device will
show up multiple times in the -t option.

Here's the output of the two things on my local laptop, with just a few
USB devices in it:

$ lsusb
Bus 004 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 003 Device 003: ID 27c6:609c Shenzhen Goodix Technology Co.,Ltd. Goodix USB2.0 MISC
Bus 003 Device 006: ID 0bda:5634 Realtek Semiconductor Corp. Laptop Camera
Bus 003 Device 004: ID 8087:0032 Intel Corp. AX210 Bluetooth
Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

$ lsusb -t
/:  Bus 04.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/4p, 10000M
/:  Bus 03.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/12p, 480M
    |__ Port 7: Dev 6, If 0, Class=Video, Driver=uvcvideo, 480M
    |__ Port 7: Dev 6, If 1, Class=Video, Driver=uvcvideo, 480M
    |__ Port 9: Dev 3, If 0, Class=Vendor Specific Class, Driver=, 12M
    |__ Port 10: Dev 4, If 0, Class=Wireless, Driver=btusb, 12M
    |__ Port 10: Dev 4, If 1, Class=Wireless, Driver=btusb, 12M
/:  Bus 02.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/4p, 20000M/x2
/:  Bus 01.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/1p, 480M

and then if you give the -v option as well you see a bit more:

$ lsusb -tv
/:  Bus 04.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/4p, 10000M
    ID 1d6b:0003 Linux Foundation 3.0 root hub
/:  Bus 03.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/12p, 480M
    ID 1d6b:0002 Linux Foundation 2.0 root hub
    |__ Port 7: Dev 6, If 0, Class=Video, Driver=uvcvideo, 480M
        ID 0bda:5634 Realtek Semiconductor Corp.
    |__ Port 7: Dev 6, If 1, Class=Video, Driver=uvcvideo, 480M
        ID 0bda:5634 Realtek Semiconductor Corp.
    |__ Port 9: Dev 3, If 0, Class=Vendor Specific Class, Driver=, 12M
        ID 27c6:609c Shenzhen Goodix Technology Co.,Ltd.
    |__ Port 10: Dev 4, If 0, Class=Wireless, Driver=btusb, 12M
        ID 8087:0032 Intel Corp. AX210 Bluetooth
    |__ Port 10: Dev 4, If 1, Class=Wireless, Driver=btusb, 12M
        ID 8087:0032 Intel Corp. AX210 Bluetooth
/:  Bus 02.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/4p, 20000M/x2
    ID 1d6b:0003 Linux Foundation 3.0 root hub
/:  Bus 01.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/1p, 480M
    ID 1d6b:0002 Linux Foundation 2.0 root hub


What are you seeing missing in your output?

thanks,

greg k-h