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Re: question about usb socket on front panel




On Wed, 12 Dec 2018 at 15:05, Long Wind <longwind2@xxxxxxxxx> wrote:
>
> below are output of three commands on lenovo
>
> lsusb
> Bus 002 Device 007: ID 25a7:2402
> Bus 002 Device 005: ID 148f:3070 Ralink Technology, Corp. RT2870/RT3070 Wireless Adapter
> Bus 002 Device 003: ID 14cd:8601 Super Top
> Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
> Bus 005 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
> Bus 004 Device 002: ID 046d:c534 Logitech, Inc. Unifying Receiver
> Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
> Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
> Bus 001 Device 002: ID 1c4f:0002 SiGma Micro Keyboard TRACER Gamma Ivory
> Bus 001 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
>
> lsusb -t
> /:  Bus 05.Port 1: Dev 1, Class=root_hub, Driver=uhci_hcd/2p, 12M
> /:  Bus 04.Port 1: Dev 1, Class=root_hub, Driver=uhci_hcd/2p, 12M
>     |__ Port 2: Dev 2, If 0, Class=Human Interface Device, Driver=usbhid, 12M
>     |__ Port 2: Dev 2, If 1, Class=Human Interface Device, Driver=usbhid, 12M
> /:  Bus 03.Port 1: Dev 1, Class=root_hub, Driver=uhci_hcd/2p, 12M
> /:  Bus 02.Port 1: Dev 1, Class=root_hub, Driver=ehci-pci/8p, 480M
>     |__ Port 3: Dev 3, If 0, Class=Hub, Driver=hub/4p, 480M
>         |__ Port 3: Dev 5, If 0, Class=Vendor Specific Class, Driver=rt2800usb, 480M
>         |__ Port 4: Dev 7, If 0, Class=Human Interface Device, Driver=usbhid, 12M
>         |__ Port 4: Dev 7, If 1, Class=Human Interface Device, Driver=usbhid, 12M
> /:  Bus 01.Port 1: Dev 1, Class=root_hub, Driver=uhci_hcd/2p, 12M
>     |__ Port 1: Dev 2, If 0, Class=Human Interface Device, Driver=usbhid, 1.5M
>     |__ Port 1: Dev 2, If 1, Class=Human Interface Device, Driver=usbhid, 1.5M

First, your original question:
> there are two usb sockets on front panel of pc case
> they appear same, but really are not
> wireless mouse can only be connected to one of them
> could you tell me their difference? Thanks!

The instructions for Windows and Mac for the wireless mouse
receiver are here: https://support.logitech.com/en_us/article/unifying-pairing
I do not know, but I wonder if you move the receiver to a different USB
socket then perhaps it won't work until you repeat the pairing procedure,
whatever that is on Linux.

Now some information how you can tell if the USB sockets are different.

If you run
# lsusb | grep 'Device 001'
you will see:
Bus 005 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub

which shows that the CPU can access 5 different USB busses.
Some of these are for internal use only, or maybe not even used
at all. Some of them will be used to provide the external USB
sockets where you can physically plug devices.
Each bus marked 1.1 has a maximum speed of 12 megabit/s.
Each bus marked 2.0 has a maximum speed of 480 megabit/s.
Each bus marked 3.0 has a maximum speed maybe up to 10 gigabit/s.

So we can see that the only USB bus on your system that is
capable of 480 megabit/s is Bus 002.

If you run
# lsusb | grep 'Device 00[^1]'
you will see:
Bus 004 Device 002: ID 046d:c534 Logitech, Inc. Unifying Receiver
Bus 002 Device 007: ID 25a7:2402
Bus 002 Device 005: ID 148f:3070 Ralink Technology, Corp.
RT2870/RT3070 Wireless Adapter
Bus 002 Device 003: ID 14cd:8601 Super Top
Bus 001 Device 002: ID 1c4f:0002 SiGma Micro Keyboard TRACER Gamma Ivory

which shows that:
Logitec Unifying Receiver (wireless mouse receiver) is on Bus 004, see
reference [1].
An device made by Areson Technology (unknown) is on Bus 002, see reference [2].
An Ralink RT2870/RT3070 Wireless Adapter (wifi) is on Bus 002, see
reference [3].
A Super Top 4-port hub is on Bus 002, see reference [4].
A SiGma Micro Keyboard TRACER Gamma Ivory keyboard is on Bus 001, see
reference [5].

[1] https://usb-ids.gowdy.us/read/UD/046d/c534
[2] https://usb-ids.gowdy.us/read/UD/25a7
[3] https://usb-ids.gowdy.us/read/UD/148f/3070
[4] https://usb-ids.gowdy.us/read/UD/14cd/8601
[5] https://usb-ids.gowdy.us/read/UD/1c4f/0002

Now, if you run 'lsusb -t' it seems that:
The Logitec Unifying Receiver connected to Port 2 of Bus 004 (12 Mb/s).
The Super Top hub is connected to Port 3 of Bus 002 (480 Mb/s).
The Ralink wifi is connected to Port 3 of the Super Top hub on Bus 002.
The Areson Technology device is connected to Port 4 of the Super Top
hub on Bus 002.
The SiGma keyboard is connected to Port 1 of Bus 01 (12 Mb/s).

Now, you can use this information to find more information that could answer
your question asking if the two front panel USB sockets are different.
Try plugging different devices into these two sockets, and repeat the
above tests, until you can answer these questions:

What is the Bus number of each socket?
What is the Port number of each socket?

With that information, and the above commands, you will be able to see
if there is any difference between the two sockets.

I don't have any expertise in this area, I'm just replying as a learning
exercise and because it appears no-one else has, and of course if I
have made any errors or if there is a better method then I will be very
happy to be corrected :)