Re: Understanding 'lsusb -t'

[Greg KH <greg@kroah.com>]

On Sat, Aug 31, 2024 at 12:07:32AM +1000, Eyal Lebedinsky wrote:
> On 30/8/24 10:32 pm, Greg KH wrote:
> > On Fri, Aug 30, 2024 at 10:14:20PM +1000, Eyal Lebedinsky wrote:
> > > I assume that the generated list is a tree, so each leaf (Device/If) is on only one point.
> > > 
> > > I note this output:
> > > 
> > > $ lsusb -tv
> > > /:  Bus 001.Port 001: Dev 001, Class=root_hub, Driver=xhci_hcd/16p, 480M
> > >      ID 1d6b:0002 Linux Foundation 2.0 root hub
> > > [trimmed]
> > >      |__ Port 004: Dev 004, If 0, Class=Hub, Driver=hub/4p, 480M
> > > [trimmed]
> > >      |__ Port 005: Dev 006, If 0, Class=Hub, Driver=hub/4p, 480M
> > > [trimmed]
> > >      |__ Port 006: Dev 019, If 0, Class=Hub, Driver=hub/4p, 480M
> > >          ID 2109:2817 VIA Labs, Inc.
> > > /:  Bus 002.Port 001: Dev 001, Class=root_hub, Driver=xhci_hcd/10p, 10000M
> > > [trimmed]
> > >      |__ Port 006: Dev 006, If 0, Class=Hub, Driver=hub/4p, 5000M
> > >          ID 2109:0817 VIA Labs, Inc.
> > > 
> > > I removed some content that is not relevant to my question.
> > > 
> > > Note the Bus 001.Port 006 and Bus 002.Port 006 entries.
> > > 
> > > I verified that both are for the same (one) device. They do not show when I disconnect it.
> > > The device is an external 4-port USB3.0 hub. It is listed once as 480M and once as 5000M.
> > > Nothing is plugged into any of the four ports.
> > > 
> > > Is this correct? Why does this device show twice in the list?
> > 
> > That's odd, as the same device shouldn't be on multiple busses.  Busses
> > are a "root port" on the system (i.e. a new PCI controller device), so
> > are you sure you just don't have multiple devices with the same
> > device/vendor id?
> > 
> > What is the diff between running the command before and after removing a
> > single device?
> > 
> > thanks,
> > 
> > greg k-h
> 
> BTW, I run a nightly log of system commands which includes lsusb.
> The first time the device is listed twice is:
> 
> $ uname -a
> Linux e7.eyal.emu.id.au 6.9.11-200.fc40.x86_64 #1 SMP PREEMPT_DYNAMIC Thu Jul 25 18:17:34 UTC 2024 x86_64 GNU/Linux

Ah, something has changed, that's more interesting.

Any way you can use 'git bisect' to see where it changed?

> $ lsusb --version
> lsusb (usbutils) 017

Did this get upgraded from an older version?

Do you see the same thing if you run 'usb-devices' before and after
(i.e. 2 devices being added)?  How about just a normal 'lsusb'?

thanks,

greg k-h