为什么 udev USB 端口修复规则不起作用？

Question

我在用着Ubuntu 16.04.1 服务器。有一个调制解调器池连接到一服务器的 USB 端口。当调制解调器关闭并重新打开时，ttyUSB数字会发生变化。我需要修复该端口。因此，我将下面的规则放入下面的文件中/etc/udev/rules.d并重新启动udev服务systemctl restart udev.service

# cat /etc/udev/rules.d/86-persistent-gsm-modem.rules 

KERNEL=="ttyUSB*", SUBSYSTEM=="tty", KERNELS=="1-1.5:1.0", DRIVERS=="ftdi_sio", ATTRS{product}=="Quad RS232-HS", ATTRS{manufacturer}=="FTDI", NAME="ttyUSB0"
KERNEL=="ttyUSB*", SUBSYSTEM=="tty", KERNELS=="1-1.5:1.1", DRIVERS=="ftdi_sio", ATTRS{product}=="Quad RS232-HS", ATTRS{manufacturer}=="FTDI", NAME="ttyUSB1"
KERNEL=="ttyUSB*", SUBSYSTEM=="tty", KERNELS=="1-1.5:1.2", DRIVERS=="ftdi_sio", ATTRS{product}=="Quad RS232-HS", ATTRS{manufacturer}=="FTDI", NAME="ttyUSB2"
KERNEL=="ttyUSB*", SUBSYSTEM=="tty", KERNELS=="1-1.5:1.3", DRIVERS=="ftdi_sio", ATTRS{product}=="Quad RS232-HS", ATTRS{manufacturer}=="FTDI", NAME="ttyUSB3"

当我关闭并再次打开调制解调器时，ttyUSB数字仍在变化。

规则是否有问题？如何检查规则是否已被阅读？udev并执行了？

例如，为 /dev/ttyUSB0 添加 udevadm 输出。

udevadm info -a /dev/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/pci0000:00/0000:00:1a.0/usb1/1-1/1-1.5/1-1.5:1.0/ttyUSB0/tty/ttyUSB0':
    KERNEL=="ttyUSB0"
    SUBSYSTEM=="tty"
    DRIVER==""

  looking at parent device '/devices/pci0000:00/0000:00:1a.0/usb1/1-1/1-1.5/1-1.5:1.0/ttyUSB0':
    KERNELS=="ttyUSB0"
    SUBSYSTEMS=="usb-serial"
    DRIVERS=="ftdi_sio"
    ATTRS{latency_timer}=="1"
    ATTRS{port_number}=="0"

  looking at parent device '/devices/pci0000:00/0000:00:1a.0/usb1/1-1/1-1.5/1-1.5:1.0':
    KERNELS=="1-1.5:1.0"
    SUBSYSTEMS=="usb"
    DRIVERS=="ftdi_sio"
    ATTRS{authorized}=="1"
    ATTRS{bAlternateSetting}==" 0"
    ATTRS{bInterfaceClass}=="ff"
    ATTRS{bInterfaceNumber}=="00"
    ATTRS{bInterfaceProtocol}=="ff"
    ATTRS{bInterfaceSubClass}=="ff"
    ATTRS{bNumEndpoints}=="02"
    ATTRS{interface}=="Quad RS232-HS"
    ATTRS{supports_autosuspend}=="1"

  looking at parent device '/devices/pci0000:00/0000:00:1a.0/usb1/1-1/1-1.5':
    KERNELS=="1-1.5"
    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}=="500mA"
    ATTRS{bNumConfigurations}=="1"
    ATTRS{bNumInterfaces}==" 4"
    ATTRS{bcdDevice}=="0800"
    ATTRS{bmAttributes}=="80"
    ATTRS{busnum}=="1"
    ATTRS{configuration}==""
    ATTRS{devnum}=="3"
    ATTRS{devpath}=="1.5"
    ATTRS{idProduct}=="6011"
    ATTRS{idVendor}=="0403"
    ATTRS{ltm_capable}=="no"
    ATTRS{manufacturer}=="FTDI"
    ATTRS{maxchild}=="0"
    ATTRS{product}=="Quad RS232-HS"
    ATTRS{quirks}=="0x0"
    ATTRS{removable}=="unknown"
    ATTRS{speed}=="480"
    ATTRS{urbnum}=="4960883"
    ATTRS{version}==" 2.00"

  looking at parent device '/devices/pci0000:00/0000:00:1a.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}=="01"
    ATTRS{bDeviceSubClass}=="00"
    ATTRS{bMaxPacketSize0}=="64"
    ATTRS{bMaxPower}=="0mA"
    ATTRS{bNumConfigurations}=="1"
    ATTRS{bNumInterfaces}==" 1"
    ATTRS{bcdDevice}=="0000"
    ATTRS{bmAttributes}=="e0"
    ATTRS{busnum}=="1"
    ATTRS{configuration}==""
    ATTRS{devnum}=="2"
    ATTRS{devpath}=="1"
    ATTRS{idProduct}=="0020"
    ATTRS{idVendor}=="8087"
    ATTRS{ltm_capable}=="no"
    ATTRS{maxchild}=="6"
    ATTRS{quirks}=="0x0"
    ATTRS{removable}=="fixed"
    ATTRS{speed}=="480"
    ATTRS{urbnum}=="31"
    ATTRS{version}==" 2.00"

  looking at parent device '/devices/pci0000:00/0000:00:1a.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}=="00"
    ATTRS{bDeviceSubClass}=="00"
    ATTRS{bMaxPacketSize0}=="64"
    ATTRS{bMaxPower}=="0mA"
    ATTRS{bNumConfigurations}=="1"
    ATTRS{bNumInterfaces}==" 1"
    ATTRS{bcdDevice}=="0404"
    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 4.4.0-34-generic ehci_hcd"
    ATTRS{maxchild}=="2"
    ATTRS{product}=="EHCI Host Controller"
    ATTRS{quirks}=="0x0"
    ATTRS{removable}=="unknown"
    ATTRS{serial}=="0000:00:1a.0"
    ATTRS{speed}=="480"
    ATTRS{urbnum}=="24"
    ATTRS{version}==" 2.00"

  looking at parent device '/devices/pci0000:00/0000:00:1a.0':
    KERNELS=="0000:00:1a.0"
    SUBSYSTEMS=="pci"
    DRIVERS=="ehci-pci"
    ATTRS{broken_parity_status}=="0"
    ATTRS{class}=="0x0c0320"
    ATTRS{companion}==""
    ATTRS{consistent_dma_mask_bits}=="32"
    ATTRS{d3cold_allowed}=="1"
    ATTRS{device}=="0x3b3c"
    ATTRS{dma_mask_bits}=="32"
    ATTRS{driver_override}=="(null)"
    ATTRS{enable}=="1"
    ATTRS{irq}=="16"
    ATTRS{local_cpulist}=="0-3"
    ATTRS{local_cpus}=="000f"
    ATTRS{msi_bus}=="1"
    ATTRS{numa_node}=="-1"
    ATTRS{subsystem_device}=="0x8383"
    ATTRS{subsystem_vendor}=="0x1043"
    ATTRS{uframe_periodic_max}=="100"
    ATTRS{vendor}=="0x8086"

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

Answer 1

首先，udev 将不再重命名内核指定的设备名称。（除其他原因外，它应该如何处理被要求重命名为已被其他设备占用的名称？）

相反，使用SYMLINK+="..."在 /dev 下创建符号链接，并使用您选择的名称，例如SYMLINK+="ttyUSB-port0"。 （实际上，标准 60-serial.rules 应该已经/dev/serial/by-path为您创建了符号链接。）

第二，规则处理不是当 udev 启动时，但只有当内核发出事件表示有新的或已更改的设备。要手动触发这些，您需要udevadm trigger -s tty（或只需重新连接设备）。