Maybe the cable is bad?

[Tom Horsley]

I was getting an infinite number of "Maybe the cable is bad"
errors in dmesg about a usb port.

It insisted on referring to "usb2-port5" when everything
else in linux talks about things like 0000:00:14.0
or lsusb says things like Bus 001 Device 004.

Is there some reference somewhere on the internet
to translate between all the different ways
linux talks about usb ports? It would be really handy
to be able to know what it is talking about instead
of having to unplug every usb cable one at a time.

Incidentally:

Bus 002 Device 005: ID 045b:0210 Hitachi, Ltd

is an external usb disk and is definitely NOT
the usb2-port5 it was yelling about. That message
finally stopped when I unplugged a USB hub
that lsusb didn't mention 2 or 5 about :-(.

(I think I plugged a well and truly broken usb
device into the hub a day or so ago and it permanently
confused it till I unplugged the hub - that device
now resides in the electronics recycle bin at
the nearby dump :-).

[Samuel Sieb]

On 8/14/20 8:30 PM, Tom Horsley wrote:
> I was getting an infinite number of "Maybe the cable is bad"
> errors in dmesg about a usb port.
>
> It insisted on referring to "usb2-port5" when everything
> else in linux talks about things like 0000:00:14.0
> or lsusb says things like Bus 001 Device 004.
>
> Is there some reference somewhere on the internet
> to translate between all the different ways
> linux talks about usb ports? It would be really handy
> to be able to know what it is talking about instead
> of having to unplug every usb cable one at a time.

The answer is yes!

The "0000:00:14.0" is referring to the PCI device that is the top-level 
USB interface.  That is the source of the "bus".

By default, lsusb shows you the bus and device number.  The device 
number is a sequentially assigned number that is unique on the whole 
bus.  It has nothing to do with the physical ports.

For the physical ports, in the journal you'll see lines like:
kernel: usb 2-1.3.1: new full-speed USB device number 33 using ehci-pci
That's bus 2, port 1, port 3, port 1.  Three levels of hubs (I plugged 
in an external hub to get that.)
If you look in /sys/bus/usb/devices, there's a directory for every 
active port and USB device.  There's a lot of info in there.

But the easiest method is: "lsusb -t"