linux的usb与sys,Linux usb filesystem

Bertha 。 2022-10-20 12:15 67阅读 0赞

Linux usb 文件系统命名规则

The generic form is

X-Y.Z:A.B

Each field identify the connection point of your device. The first two field are mandatory:

X is the USB bus of your motherboard where is connected the USB system.

Y is the port in use on the bus system

So the USB device identified with the string 3-3 is the device connected on the port 3 of the bus 3.

If you connect an USB hub, you are extending the connection capability of a single USB port. The Linux kernel identify this situation by appending the Z field.

Z is the port is use on an hub

So, the USB device identified with the string 1-2.5 is the device connected on the port 5 of the hub connected on the port 2 of the bus 1.

USB specification allow you to connect in cascade more then one USB hub, so the Linux kernel continue to append the port in use on the different hubs. So, the USB device identified with the string 1-2.1.1 is the device connected on the port 1 of the hub connected on the port 1 of the hub connected to the port 2 of the bus 1.

A fast way to retrieve these information is to read the kernel messages (if you can).

$ dmesg | grep usb

\[... snip ...\]

\[ 2.047950\] usb 4-1: new full-speed USB device number 2 using ohci\_hcd

\[ 2.202628\] usb 4-1: New USB device found, idVendor=046d, idProduct=c318

\[ 2.202638\] usb 4-1: New USB device strings: Mfr=1, Product=2, SerialNumber=0

\[ 2.202643\] usb 4-1: Product: Logitech Illuminated Keyboard

\[ 2.202648\] usb 4-1: Manufacturer: Logitech

\[... snip ...\]

Then, the last two fields of the pattern (after colon) identify an internal section of an USB device :

A is the configuration number of the device

B is the interface number of a configuration