udev：如何识别sys设备所属的物理设备？

Question

我有几个 USB 调制解调器，每个调制解调器都有多个端点：许多 TTY、一个网络接口、一个 cdc-wdm 端口和其他一些东西。我试图将它们组合在一起，以便我知道，例如，ttyUSB3、ttyUSB4、wwan1 和 cdc-wdm1 都属于同一个物理 USB 设备。

我认为$id应该识别物理设备，所以我尝试$id使用ENV{id}=$id. 这似乎适用于网络接口和串行端口，但不适用于 cdc-wdm 端口（这些端口的 id 未设置）。

以下是添加ENV{id}=$id规则后的一些示例数据：

规则： SUBSYSTEM=="net", ATTRS{idVendor}=="106c", ATTRS{idProduct}=="3718", ENV{id}="$id"

# udevadm info --query=all --path=/devices/platform/atmel-ehci/usb1/1-1/1-1.3/1-
1.3:1.5/net/wwan0
P: /devices/platform/atmel-ehci/usb1/1-1/1-1.3/1-1.3:1.5/net/wwan0
E: DEVPATH=/devices/platform/atmel-ehci/usb1/1-1/1-1.3/1-1.3:1.5/net/wwan0
E: DEVTYPE=wwan
E: ID_BUS=usb
E: ID_MODEL=PANTECH_UML290
E: ID_MODEL_ENC=PANTECH\x20UML290
E: ID_MODEL_ID=3718
E: ID_REVISION=0000
E: ID_SERIAL=Pantech__Incorporated_PANTECH_UML290
E: ID_TYPE=generic
E: ID_USB_DRIVER=qmi_wwan
E: ID_USB_INTERFACES=:020201:0a0000:ffffff:fffdff:fffeff:fff1ff:
E: ID_USB_INTERFACE_NUM=05
E: ID_VENDOR=Pantech__Incorporated
E: ID_VENDOR_ENC=Pantech\x2c\x20Incorporated
E: ID_VENDOR_ID=106c
E: IFINDEX=5
E: INTERFACE=wwan0
E: SUBSYSTEM=net
E: USEC_INITIALIZED=174833330
E: id=1-1.3

规则： SUBSYSTEM=="usb", KERNEL=="*cdc-wdm*", ENV{id}="$id"

# udevadm info --query=all --path=/devices/platform/atmel-ehci/usb1/1-1/1-1.3/1-
1.3:1.5/usb/cdc-wdm0
P: /devices/platform/atmel-ehci/usb1/1-1/1-1.3/1-1.3:1.5/usb/cdc-wdm0
N: cdc-wdm0
E: DEVNAME=/dev/cdc-wdm0
E: DEVPATH=/devices/platform/atmel-ehci/usb1/1-1/1-1.3/1-1.3:1.5/usb/cdc-wdm0
E: MAJOR=180
E: MINOR=176
E: SUBSYSTEM=usb
E: USEC_INITIALIZED=174788259

Answer 1

好的，首先我现在了解文档的$id含义

在向上搜索 devpath 以查找 SUBSYSTEMS、KERNELS、DRIVERS 和 ATTRS 时匹配的设备名称。

...这不是我所想的（这是由于无法理解文档并结合一些实验而形成的）。

通过“设备名称”，它与KERNEL密钥匹配的内容相同。文档说的KERNEL关键是：

匹配事件设备的名称。

这就是您知道“名称”和“内核”相关的方式。

“在向上搜索开发路径以查找 SUBSYSTEMS、KERNELS、DRIVERS 和 ATTRS 时匹配”部分意味着如果您在规则中指定了“SUBSYSTEMS、KERNELS、DRIVERS 或 ATTRS”匹配，它将沿着设备树向上走，直到找到一个比赛; 将使用匹配设备的名称。

因此，在我的第一条规则中，它与 ATTRS 密钥匹配，而该设备恰好是物理 USB 设备。

现在对于我的另一条规则，我必须查看树并找到与物理设备匹配但不匹配其下方的任何内容。这是我的设备树：

# udevadm info --attribute-walk --name=/dev/cdc-wdm0

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/platform/atmel-ehci/usb1/1-1/1-1.7/1-1.7.2/1-1.7.2:1.5/usb/cdc-wdm0':
    KERNEL=="cdc-wdm0"
    SUBSYSTEM=="usb"
    DRIVER==""

  looking at parent device '/devices/platform/atmel-ehci/usb1/1-1/1-1.7/1-1.7.2/1-1.7.2:1.5':
    KERNELS=="1-1.7.2:1.5"
    SUBSYSTEMS=="usb"
    DRIVERS=="qmi_wwan"
    ATTRS{bInterfaceNumber}=="05"
    ATTRS{bAlternateSetting}==" 0"
    ATTRS{bNumEndpoints}=="03"
    ATTRS{bInterfaceClass}=="ff"
    ATTRS{bInterfaceSubClass}=="f1"
    ATTRS{bInterfaceProtocol}=="ff"
    ATTRS{supports_autosuspend}=="1"

  looking at parent device '/devices/platform/atmel-ehci/usb1/1-1/1-1.7/1-1.7.2':
    KERNELS=="1-1.7.2"
    SUBSYSTEMS=="usb"
    DRIVERS=="usb"
    ATTRS{configuration}=="Pantech, Incorporated"
    ATTRS{bNumInterfaces}==" 6"
    ATTRS{bConfigurationValue}=="1"
    ATTRS{bmAttributes}=="c0"
    ATTRS{bMaxPower}=="500mA"
    ATTRS{urbnum}=="496"
    ATTRS{idVendor}=="106c"
    ATTRS{idProduct}=="3718"
    ATTRS{bcdDevice}=="0000"
    ATTRS{bDeviceClass}=="02"
    ATTRS{bDeviceSubClass}=="00"
    ATTRS{bDeviceProtocol}=="00"
    ATTRS{bNumConfigurations}=="1"
    ATTRS{bMaxPacketSize0}=="64"
    ATTRS{speed}=="480"
    ATTRS{busnum}=="1"
    ATTRS{devnum}=="12"
    ATTRS{devpath}=="1.7.2"
    ATTRS{version}==" 2.00"
    ATTRS{maxchild}=="0"
    ATTRS{quirks}=="0x0"
    ATTRS{avoid_reset_quirk}=="0"
    ATTRS{authorized}=="1"
    ATTRS{manufacturer}=="Pantech, Incorporated"
    ATTRS{product}=="PANTECH UML290"

  looking at parent device '/devices/platform/atmel-ehci/usb1/1-1/1-1.7':
    KERNELS=="1-1.7"
    SUBSYSTEMS=="usb"
    DRIVERS=="usb"
    ATTRS{configuration}==""
    ATTRS{bNumInterfaces}==" 1"
    ATTRS{bConfigurationValue}=="1"
    ATTRS{bmAttributes}=="e0"
    ATTRS{bMaxPower}=="100mA"
    ATTRS{urbnum}=="188"
    ATTRS{idVendor}=="1a40"
    ATTRS{idProduct}=="0101"
    ATTRS{bcdDevice}=="0111"
    ATTRS{bDeviceClass}=="09"
    ATTRS{bDeviceSubClass}=="00"
    ATTRS{bDeviceProtocol}=="01"
    ATTRS{bNumConfigurations}=="1"
    ATTRS{bMaxPacketSize0}=="64"
    ATTRS{speed}=="480"
    ATTRS{busnum}=="1"
    ATTRS{devnum}=="3"
    ATTRS{devpath}=="1.7"
    ATTRS{version}==" 2.00"
    ATTRS{maxchild}=="4"
    ATTRS{quirks}=="0x0"
    ATTRS{avoid_reset_quirk}=="0"
    ATTRS{authorized}=="1"
    ATTRS{product}=="USB 2.0 Hub"

  looking at parent device '/devices/platform/atmel-ehci/usb1/1-1':
    KERNELS=="1-1"
    SUBSYSTEMS=="usb"
    DRIVERS=="usb"
    ATTRS{configuration}==""
    ATTRS{bNumInterfaces}==" 1"
    ATTRS{bConfigurationValue}=="1"
    ATTRS{bmAttributes}=="e0"
    ATTRS{bMaxPower}=="100mA"
    ATTRS{urbnum}=="53"
    ATTRS{idVendor}=="1a40"
    ATTRS{idProduct}=="0201"
    ATTRS{bcdDevice}=="0100"
    ATTRS{bDeviceClass}=="09"
    ATTRS{bDeviceSubClass}=="00"
    ATTRS{bDeviceProtocol}=="02"
    ATTRS{bNumConfigurations}=="1"
    ATTRS{bMaxPacketSize0}=="64"
    ATTRS{speed}=="480"
    ATTRS{busnum}=="1"
    ATTRS{devnum}=="2"
    ATTRS{devpath}=="1"
    ATTRS{version}==" 2.00"
    ATTRS{maxchild}=="7"
    ATTRS{quirks}=="0x0"
    ATTRS{avoid_reset_quirk}=="0"
    ATTRS{authorized}=="1"
    ATTRS{product}=="USB 2.0 Hub [MTT]"

  looking at parent device '/devices/platform/atmel-ehci/usb1':
    KERNELS=="usb1"
    SUBSYSTEMS=="usb"
    DRIVERS=="usb"
    ATTRS{configuration}==""
    ATTRS{bNumInterfaces}==" 1"
    ATTRS{bConfigurationValue}=="1"
    ATTRS{bmAttributes}=="e0"
    ATTRS{bMaxPower}=="  0mA"
    ATTRS{urbnum}=="26"
    ATTRS{idVendor}=="1d6b"
    ATTRS{idProduct}=="0002"
    ATTRS{bcdDevice}=="0206"
    ATTRS{bDeviceClass}=="09"
    ATTRS{bDeviceSubClass}=="00"
    ATTRS{bDeviceProtocol}=="00"
    ATTRS{bNumConfigurations}=="1"
    ATTRS{bMaxPacketSize0}=="64"
    ATTRS{speed}=="480"
    ATTRS{busnum}=="1"
    ATTRS{devnum}=="1"
    ATTRS{devpath}=="0"
    ATTRS{version}==" 2.00"
    ATTRS{maxchild}=="3"
    ATTRS{quirks}=="0x0"
    ATTRS{avoid_reset_quirk}=="0"
    ATTRS{authorized}=="1"
    ATTRS{manufacturer}=="Linux 2.6.39.4-acnbfx100 ehci_hcd"
    ATTRS{product}=="Atmel EHCI UHP HS"
    ATTRS{serial}=="atmel-ehci"
    ATTRS{authorized_default}=="1"

  looking at parent device '/devices/platform/atmel-ehci':
    KERNELS=="atmel-ehci"
    SUBSYSTEMS=="platform"
    DRIVERS=="atmel-ehci"
    ATTRS{companion}==""

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

我要匹配的设备是/devices/platform/atmel-ehci/usb1/1-1/1-1.7/1-1.7.2'. 您可以看到该设备的驱动程序是“usb”，它下面的任何内容都不匹配。以下规则解决了我的问题，甚至应该是一个通用的解决方案，因为我很确定 USB 驱动程序不会处理设备的端点。

DRIVERS=="usb", KERNEL=="*cdc-wdm*", ENV{id}="$id", RUN="/usr/local/bin/modem_setup.sh"

这就是我一直在寻找的结果：

# udevadm info --query=all --name=/dev/cdc-wdm0
P: /devices/platform/atmel-ehci/usb1/1-1/1-1.7/1-1.7.2/1-1.7.2:1.5/usb/cdc-wdm0
N: cdc-wdm0
E: DEVNAME=/dev/cdc-wdm0
E: DEVPATH=/devices/platform/atmel-ehci/usb1/1-1/1-1.7/1-1.7.2/1-1.7.2:1.5/usb/cdc-wdm0
E: MAJOR=180
E: MINOR=176
E: SUBSYSTEM=usb
E: USEC_INITIALIZED=12243969
E: id=1-1.7.2