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I have two lidars. And in my code I need to provide the lidar port: ttyUSB0/ttyUSB1 etc...

I have this udev rule. (/etc/udev/rules.d/rplidar.rules) rplidar.rules

# set the udev rule , make the device_port be fixed by rplidar
#
KERNEL=="ttyUSB*", ATTRS{idVendor}=="10c4", ATTRS{idProduct}=="ea60", MODE:="0777", SYMLINK+="rplidar"

By making this I can simply call port=rplidar in my code. But now I have two rplidars that have the same idVendor and idProduct, how can I distinguish them and create an additional rule for the second lidar?

When I plugged in only one device, this is how I did it

$ udevadm info -a -n /ttyUSB0
Udevadm info starts with the device specified by the devpath and then
walks up the chain of parent devices. It prints for every device
found, all possible attributes in the udev rules key format.
A rule to match, can be composed by the attributes of the device
and the attributes from one single parent device.

  looking at device '/devices/pci0000:00/0000:00:14.0/usb1/1-1/1-1.1/1-1.1:1.0/ttyUSB0/tty/ttyUSB0':
    KERNEL=="ttyUSB0"
    SUBSYSTEM=="tty"
    DRIVER==""

  looking at parent device '/devices/pci0000:00/0000:00:14.0/usb1/1-1/1-1.1/1-1.1:1.0/ttyUSB0':
    KERNELS=="ttyUSB0"
    SUBSYSTEMS=="usb-serial"
    DRIVERS=="cp210x"
    ATTRS{port_number}=="0"

  looking at parent device '/devices/pci0000:00/0000:00:14.0/usb1/1-1/1-1.1/1-1.1:1.0':
    KERNELS=="1-1.1:1.0"
    SUBSYSTEMS=="usb"
    DRIVERS=="cp210x"
    ATTRS{authorized}=="1"
    ATTRS{bAlternateSetting}==" 0"
    ATTRS{bInterfaceClass}=="ff"
    ATTRS{bInterfaceNumber}=="00"
    ATTRS{bInterfaceProtocol}=="00"
    ATTRS{bInterfaceSubClass}=="00"
    ATTRS{bNumEndpoints}=="02"
    ATTRS{interface}=="CP2102 USB to UART Bridge Controller"
    ATTRS{supports_autosuspend}=="1"

  looking at parent device '/devices/pci0000:00/0000:00:14.0/usb1/1-1/1-1.1':
    KERNELS=="1-1.1"
    SUBSYSTEMS=="usb"
    DRIVERS=="usb"
    ATTRS{authorized}=="1"
    ATTRS{avoid_reset_quirk}=="0"
    ATTRS{bConfigurationValue}=="1"
    ATTRS{bDeviceClass}=="00"
    ATTRS{bDeviceProtocol}=="00"
    ATTRS{bDeviceSubClass}=="00"
    ATTRS{bMaxPacketSize0}=="64"
    ATTRS{bMaxPower}=="100mA"
    ATTRS{bNumConfigurations}=="1"
    ATTRS{bNumInterfaces}==" 1"
    ATTRS{bcdDevice}=="0100"
    ATTRS{bmAttributes}=="80"
    ATTRS{busnum}=="1"
    ATTRS{configuration}==""
    ATTRS{devnum}=="28"
    ATTRS{devpath}=="1.1"
    ATTRS{idProduct}=="ea60"
    ATTRS{idVendor}=="10c4"
    ATTRS{ltm_capable}=="no"
    ATTRS{manufacturer}=="Silicon Labs"
    ATTRS{maxchild}=="0"
    ATTRS{product}=="CP2102 USB to UART Bridge Controller"
    ATTRS{quirks}=="0x0"
    ATTRS{removable}=="unknown"
    ATTRS{serial}=="0001"
    ATTRS{speed}=="12"
    ATTRS{urbnum}=="17"
    ATTRS{version}==" 1.10"

  looking at parent device '/devices/pci0000:00/0000:00:14.0/usb1/1-1':
    KERNELS=="1-1"
    SUBSYSTEMS=="usb"
    DRIVERS=="usb"
    ATTRS{authorized}=="1"
    ATTRS{avoid_reset_quirk}=="0"
    ATTRS{bConfigurationValue}=="1"
    ATTRS{bDeviceClass}=="09"
    ATTRS{bDeviceProtocol}=="02"
    ATTRS{bDeviceSubClass}=="00"
    ATTRS{bMaxPacketSize0}=="64"
    ATTRS{bMaxPower}=="0mA"
    ATTRS{bNumConfigurations}=="1"
    ATTRS{bNumInterfaces}==" 1"
    ATTRS{bcdDevice}=="0286"
    ATTRS{bmAttributes}=="e0"
    ATTRS{busnum}=="1"
    ATTRS{configuration}==""
    ATTRS{devnum}=="13"
    ATTRS{devpath}=="1"
    ATTRS{idProduct}=="2744"
    ATTRS{idVendor}=="0424"
    ATTRS{ltm_capable}=="no"
    ATTRS{manufacturer}=="Microchip Tech"
    ATTRS{maxchild}=="4"
    ATTRS{product}=="USB2744"
    ATTRS{quirks}=="0x0"
    ATTRS{removable}=="removable"
    ATTRS{speed}=="480"
    ATTRS{urbnum}=="331"
    ATTRS{version}==" 2.10"

  looking at parent device '/devices/pci0000:00/0000:00:14.0/usb1':
    KERNELS=="usb1"
    SUBSYSTEMS=="usb"
    DRIVERS=="usb"
    ATTRS{authorized}=="1"
    ATTRS{authorized_default}=="1"
    ATTRS{avoid_reset_quirk}=="0"
    ATTRS{bConfigurationValue}=="1"
    ATTRS{bDeviceClass}=="09"
    ATTRS{bDeviceProtocol}=="01"
    ATTRS{bDeviceSubClass}=="00"
    ATTRS{bMaxPacketSize0}=="64"
    ATTRS{bMaxPower}=="0mA"
    ATTRS{bNumConfigurations}=="1"
    ATTRS{bNumInterfaces}==" 1"
    ATTRS{bcdDevice}=="0413"
    ATTRS{bmAttributes}=="e0"
    ATTRS{busnum}=="1"
    ATTRS{configuration}==""
    ATTRS{devnum}=="1"
    ATTRS{devpath}=="0"
    ATTRS{idProduct}=="0002"
    ATTRS{idVendor}=="1d6b"
    ATTRS{interface_authorized_default}=="1"
    ATTRS{ltm_capable}=="no"
    ATTRS{manufacturer}=="Linux 4.13.0-38-generic xhci-hcd"
    ATTRS{maxchild}=="16"
    ATTRS{product}=="xHCI Host Controller"
    ATTRS{quirks}=="0x0"
    ATTRS{removable}=="unknown"
    ATTRS{serial}=="0000:00:14.0"
    ATTRS{speed}=="480"
    ATTRS{urbnum}=="75264"
    ATTRS{version}==" 2.00"

  looking at parent device '/devices/pci0000:00/0000:00:14.0':
    KERNELS=="0000:00:14.0"
    SUBSYSTEMS=="pci"
    DRIVERS=="xhci_hcd"
    ATTRS{broken_parity_status}=="0"
    ATTRS{class}=="0x0c0330"
    ATTRS{consistent_dma_mask_bits}=="64"
    ATTRS{d3cold_allowed}=="1"
    ATTRS{device}=="0xa12f"
    ATTRS{dma_mask_bits}=="64"
    ATTRS{driver_override}=="(null)"
    ATTRS{enable}=="1"
    ATTRS{irq}=="126"
    ATTRS{local_cpulist}=="0-7"
    ATTRS{local_cpus}=="ff"
    ATTRS{msi_bus}=="1"
    ATTRS{numa_node}=="-1"
    ATTRS{revision}=="0x31"
    ATTRS{subsystem_device}=="0x201f"
    ATTRS{subsystem_vendor}=="0x1043"
    ATTRS{vendor}=="0x8086"

  looking at parent device '/devices/pci0000:00':
    KERNELS=="pci0000:00"
    SUBSYSTEMS==""
    DRIVERS==""
  • Look for a serial number in the ATTRS like this one for a serial to USB adapter: SUBSYSTEM=="tty", SUBSYSTEMS=="usb", ATTRS{idVendor}=="0403", ATTRS{idProduct}=="6001", ATTRS{serial}=="A100*", SYMLINK+="ais" – Jean-Marie May 24 '18 at 12:39
  • They have same ATTRS{serial}=="0001". – BhanuKiran May 24 '18 at 13:08
  • Well then it is harder to do. You could get the development package from Silicon Labs and change the serial number of one of the devices. They are programmable. It depends on how familiar you are with such things. – Jean-Marie May 24 '18 at 13:55
  • 1
    possible duplicate of askubuntu.com/questions/49910/… – Sebastian Stark May 24 '18 at 17:00
  • Did you find a solution yet? It is not duplicate. – nurp Nov 13 '18 at 15:40
0

get the programmer from siliconelab and edit the CP2102 USB to UART Bridge Controller parametre. preaty fast to do, like 5 min The each device will have they own name and serial...

the exe we use is: install_USBXpress_SDK.exe

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