linux - 区分两个相似的USB设备

Question

这个问题之前被问过很多次，但我还没有为我的案例找到任何可行的解决方案。在我的例子中，我有两个基于 FTDI 的 USB <-> 串行转换器，我无法从中找到任何区别特征来包含在我打算编写的 udev 规则中，以便通过持久性识别它们姓名。的输出:

udevadm info --attribute-walk --path=/sys/bus/usb-serial/devices/ttyUSB0

looking at device '/devices/pci0000:00/0000:00:14.0/usb3/3-1/3-1:1.0/ttyUSB0':
    KERNEL=="ttyUSB0"
    SUBSYSTEM=="usb-serial"
    DRIVER=="ftdi_sio"
    ATTR{port_number}=="0"
    ATTR{latency_timer}=="1"

  looking at parent device '/devices/pci0000:00/0000:00:14.0/usb3/3-1/3-1:1.0':
    KERNELS=="3-1:1.0"
    SUBSYSTEMS=="usb"
    DRIVERS=="ftdi_sio"
    ATTRS{bInterfaceClass}=="ff"
    ATTRS{bInterfaceSubClass}=="ff"
    ATTRS{bInterfaceProtocol}=="ff"
    ATTRS{bNumEndpoints}=="02"
    ATTRS{supports_autosuspend}=="1"
    ATTRS{bAlternateSetting}==" 0"
    ATTRS{bInterfaceNumber}=="00"
    ATTRS{interface}=="USB <-> Serial"

  looking at parent device '/devices/pci0000:00/0000:00:14.0/usb3/3-1':
    KERNELS=="3-1"
    SUBSYSTEMS=="usb"
    DRIVERS=="usb"
    ATTRS{bDeviceSubClass}=="00"
    ATTRS{bDeviceProtocol}=="00"
    ATTRS{devpath}=="1"
    ATTRS{idVendor}=="0403"
    ATTRS{speed}=="12"
    ATTRS{bNumInterfaces}==" 1"
    ATTRS{bConfigurationValue}=="1"
    ATTRS{bMaxPacketSize0}=="8"
    ATTRS{busnum}=="3"
    ATTRS{devnum}=="21"
    ATTRS{configuration}==""
    ATTRS{bMaxPower}=="90mA"
    ATTRS{authorized}=="1"
    ATTRS{bmAttributes}=="80"
    ATTRS{bNumConfigurations}=="1"
    ATTRS{maxchild}=="0"
    ATTRS{bcdDevice}=="0400"
    ATTRS{avoid_reset_quirk}=="0"
    ATTRS{quirks}=="0x0"
    ATTRS{version}==" 1.10"
    ATTRS{urbnum}=="11"
    ATTRS{ltm_capable}=="no"
    ATTRS{manufacturer}=="FTDI"
    ATTRS{removable}=="removable"
    ATTRS{idProduct}=="6001"
    ATTRS{bDeviceClass}=="00"
    ATTRS{product}=="USB <-> Serial"

  looking at parent device '/devices/pci0000:00/0000:00:14.0/usb3':
    KERNELS=="usb3"
    SUBSYSTEMS=="usb"
    DRIVERS=="usb"
    ATTRS{bDeviceSubClass}=="00"
    ATTRS{bDeviceProtocol}=="01"
    ATTRS{devpath}=="0"
    ATTRS{idVendor}=="1d6b"
    ATTRS{speed}=="480"
    ATTRS{bNumInterfaces}==" 1"
    ATTRS{bConfigurationValue}=="1"
    ATTRS{bMaxPacketSize0}=="64"
    ATTRS{authorized_default}=="1"
    ATTRS{busnum}=="3"
    ATTRS{devnum}=="1"
    ATTRS{configuration}==""
    ATTRS{bMaxPower}=="0mA"
    ATTRS{authorized}=="1"
    ATTRS{bmAttributes}=="e0"
    ATTRS{bNumConfigurations}=="1"
    ATTRS{maxchild}=="4"
    ATTRS{bcdDevice}=="0313"
    ATTRS{avoid_reset_quirk}=="0"
    ATTRS{quirks}=="0x0"
    ATTRS{serial}=="0000:00:14.0"
    ATTRS{version}==" 2.00"
    ATTRS{urbnum}=="383"
    ATTRS{ltm_capable}=="no"
    ATTRS{manufacturer}=="Linux 3.13.0-32-generic xhci_hcd"
    ATTRS{removable}=="unknown"
    ATTRS{idProduct}=="0002"
    ATTRS{bDeviceClass}=="09"
    ATTRS{product}=="xHCI Host Controller"

  looking at parent device '/devices/pci0000:00/0000:00:14.0':
    KERNELS=="0000:00:14.0"
    SUBSYSTEMS=="pci"
    DRIVERS=="xhci_hcd"
    ATTRS{irq}=="40"
    ATTRS{subsystem_vendor}=="0x17aa"
    ATTRS{broken_parity_status}=="0"
    ATTRS{class}=="0x0c0330"
    ATTRS{enabled}=="1"
    ATTRS{consistent_dma_mask_bits}=="64"
    ATTRS{dma_mask_bits}=="64"
    ATTRS{local_cpus}=="ff"
    ATTRS{device}=="0x1e31"
    ATTRS{msi_bus}==""
    ATTRS{local_cpulist}=="0-7"
    ATTRS{vendor}=="0x8086"
    ATTRS{subsystem_device}=="0x3977"
    ATTRS{d3cold_allowed}=="1"

  looking at parent device '/devices/pci0000:00':
    KERNELS=="pci0000:00"
    SUBSYSTEMS==""
    DRIVERS==""

和 ttyUSB1 一样:

udevadm info --attribute-walk --path=/sys/bus/usb-serial/devices/ttyUSB0

looking at device '/devices/pci0000:00/0000:00:14.0/usb3/3-2/3-2:1.0/ttyUSB1':
    KERNEL=="ttyUSB1"
    SUBSYSTEM=="usb-serial"
    DRIVER=="ftdi_sio"
    ATTR{port_number}=="0"
    ATTR{latency_timer}=="1"

  looking at parent device '/devices/pci0000:00/0000:00:14.0/usb3/3-2/3-2:1.0':
    KERNELS=="3-2:1.0"
    SUBSYSTEMS=="usb"
    DRIVERS=="ftdi_sio"
    ATTRS{bInterfaceClass}=="ff"
    ATTRS{bInterfaceSubClass}=="ff"
    ATTRS{bInterfaceProtocol}=="ff"
    ATTRS{bNumEndpoints}=="02"
    ATTRS{supports_autosuspend}=="1"
    ATTRS{bAlternateSetting}==" 0"
    ATTRS{bInterfaceNumber}=="00"
    ATTRS{interface}=="USB <-> Serial"

  looking at parent device '/devices/pci0000:00/0000:00:14.0/usb3/3-2':
    KERNELS=="3-2"
    SUBSYSTEMS=="usb"
    DRIVERS=="usb"
    ATTRS{bDeviceSubClass}=="00"
    ATTRS{bDeviceProtocol}=="00"
    ATTRS{devpath}=="2"
    ATTRS{idVendor}=="0403"
    ATTRS{speed}=="12"
    ATTRS{bNumInterfaces}==" 1"
    ATTRS{bConfigurationValue}=="1"
    ATTRS{bMaxPacketSize0}=="8"
    ATTRS{busnum}=="3"
    ATTRS{devnum}=="22"
    ATTRS{configuration}==""
    ATTRS{bMaxPower}=="90mA"
    ATTRS{authorized}=="1"
    ATTRS{bmAttributes}=="80"
    ATTRS{bNumConfigurations}=="1"
    ATTRS{maxchild}=="0"
    ATTRS{bcdDevice}=="0400"
    ATTRS{avoid_reset_quirk}=="0"
    ATTRS{quirks}=="0x0"
    ATTRS{version}==" 1.10"
    ATTRS{urbnum}=="11"
    ATTRS{ltm_capable}=="no"
    ATTRS{manufacturer}=="FTDI"
    ATTRS{removable}=="removable"
    ATTRS{idProduct}=="6001"
    ATTRS{bDeviceClass}=="00"
    ATTRS{product}=="USB <-> Serial"

  looking at parent device '/devices/pci0000:00/0000:00:14.0/usb3':
    KERNELS=="usb3"
    SUBSYSTEMS=="usb"
    DRIVERS=="usb"
    ATTRS{bDeviceSubClass}=="00"
    ATTRS{bDeviceProtocol}=="01"
    ATTRS{devpath}=="0"
    ATTRS{idVendor}=="1d6b"
    ATTRS{speed}=="480"
    ATTRS{bNumInterfaces}==" 1"
    ATTRS{bConfigurationValue}=="1"
    ATTRS{bMaxPacketSize0}=="64"
    ATTRS{authorized_default}=="1"
    ATTRS{busnum}=="3"
    ATTRS{devnum}=="1"
    ATTRS{configuration}==""
    ATTRS{bMaxPower}=="0mA"
    ATTRS{authorized}=="1"
    ATTRS{bmAttributes}=="e0"
    ATTRS{bNumConfigurations}=="1"
    ATTRS{maxchild}=="4"
    ATTRS{bcdDevice}=="0313"
    ATTRS{avoid_reset_quirk}=="0"
    ATTRS{quirks}=="0x0"
    ATTRS{serial}=="0000:00:14.0"
    ATTRS{version}==" 2.00"
    ATTRS{urbnum}=="383"
    ATTRS{ltm_capable}=="no"
    ATTRS{manufacturer}=="Linux 3.13.0-32-generic xhci_hcd"
    ATTRS{removable}=="unknown"
    ATTRS{idProduct}=="0002"
    ATTRS{bDeviceClass}=="09"
    ATTRS{product}=="xHCI Host Controller"

  looking at parent device '/devices/pci0000:00/0000:00:14.0':
    KERNELS=="0000:00:14.0"
    SUBSYSTEMS=="pci"
    DRIVERS=="xhci_hcd"
    ATTRS{irq}=="40"
    ATTRS{subsystem_vendor}=="0x17aa"
    ATTRS{broken_parity_status}=="0"
    ATTRS{class}=="0x0c0330"
    ATTRS{enabled}=="1"
    ATTRS{consistent_dma_mask_bits}=="64"
    ATTRS{dma_mask_bits}=="64"
    ATTRS{local_cpus}=="ff"
    ATTRS{device}=="0x1e31"
    ATTRS{msi_bus}==""
    ATTRS{local_cpulist}=="0-7"
    ATTRS{vendor}=="0x8086"
    ATTRS{subsystem_device}=="0x3977"
    ATTRS{d3cold_allowed}=="1"

  looking at parent device '/devices/pci0000:00':
    KERNELS=="pci0000:00"
    SUBSYSTEMS==""
    DRIVERS==""

我尝试实现第一个解决方案 @ How to distinguish between identical USB-to-serial adapters?通过将 KERNELS=="3-1"分配给 ttyUSB0 并将 KERNELS=="3-2"分配给 ttyUSB1，但它不是持久的，每次我重新连接设备时都会发生变化。此外 ATTRS{devnum} 也每次都在变化，但可以注意到它们总是按顺序排列的。那么，我可以使用它们来修复设备名称吗？我不确定相同的设备是否总是使用更小或更大的 devnum 进行初始化。感谢您的帮助。

Answer 1

KERNELS 属性是设备的总线路径，只要它们始终插入同一端口就应该保持一致(如果该端口位于集线器上，则集线器插入相同的端口等)。由于这两个设备是相同的，因此除了通过它们所连接的端口外，没有其他方法可以区分它们。