udevinfo的使用

    当我们要编写一个ｕｄｅｖ规则文件时,经常用到一些内核空间导到用户空间的ｕｄｅｖ信息.如:

SUBSYSTEM=="usb"
ATTR{manufacturer}=="Sony"
ATTR{product}=="Storage Media"
ATTR{idVendor}=="054c"
ATTR{idProduct}=="0439"

　这些字眼其实可以通过ｕｄｅｖｉｎｆｏ来抓取.如我在我的UBUNTU12.10插入一个U盘.可以看到这个U盘导到用户空间的ｕｄｅｖｉｎｆｏ信息:

执行下面命令:

root@se7en-LIFEBOOK-LH531:~# udevadm info -a -p /sys/bus/usb/drivers/usb/2-1.1/

可以看到下面信息:

root@se7en-LIFEBOOK-LH531:~# udevadm info -a -p /sys/bus/usb/drivers/usb/2-1.1/

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/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.1':
    KERNEL=="2-1.1"
    SUBSYSTEM=="usb"
    DRIVER=="usb"
    ATTR{bDeviceSubClass}=="00"
    ATTR{bDeviceProtocol}=="00"
    ATTR{devpath}=="1.1"
    ATTR{idVendor}=="054c"
    ATTR{speed}=="480"
    ATTR{bNumInterfaces}==" 1"
    ATTR{bConfigurationValue}=="1"
    ATTR{bMaxPacketSize0}=="64"
    ATTR{busnum}=="2"
    ATTR{devnum}=="7"
    ATTR{configuration}==""
    ATTR{bMaxPower}=="200mA"
    ATTR{authorized}=="1"
    ATTR{bmAttributes}=="80"
    ATTR{bNumConfigurations}=="1"
    ATTR{maxchild}=="0"
    ATTR{bcdDevice}=="0100"
    ATTR{avoid_reset_quirk}=="0"
    ATTR{quirks}=="0x0"
    ATTR{serial}=="7B2211110111000199"
    ATTR{version}==" 2.00"
    ATTR{urbnum}=="1352"
    ATTR{manufacturer}=="Sony"
    ATTR{removable}=="removable"
    ATTR{idProduct}=="0439"
    ATTR{bDeviceClass}=="00"
    ATTR{product}=="Storage Media"

  looking at parent device '/devices/pci0000:00/0000:00:1d.0/usb2/2-1':
    KERNELS=="2-1"
    SUBSYSTEMS=="usb"
    DRIVERS=="usb"
    ATTRS{bDeviceSubClass}=="00"
    ATTRS{bDeviceProtocol}=="01"
    ATTRS{devpath}=="1"
    ATTRS{idVendor}=="8087"
    ATTRS{speed}=="480"
    ATTRS{bNumInterfaces}==" 1"
    ATTRS{bConfigurationValue}=="1"
    ATTRS{bMaxPacketSize0}=="64"
    ATTRS{busnum}=="2"
    ATTRS{devnum}=="2"
    ATTRS{configuration}==""
    ATTRS{bMaxPower}=="  0mA"
    ATTRS{authorized}=="1"
    ATTRS{bmAttributes}=="e0"
    ATTRS{bNumConfigurations}=="1"
    ATTRS{maxchild}=="6"
    ATTRS{bcdDevice}=="0000"
    ATTRS{avoid_reset_quirk}=="0"
    ATTRS{quirks}=="0x0"
    ATTRS{version}==" 2.00"
    ATTRS{urbnum}=="1895"
    ATTRS{removable}=="fixed"
    ATTRS{idProduct}=="0024"
    ATTRS{bDeviceClass}=="09"

  looking at parent device '/devices/pci0000:00/0000:00:1d.0/usb2':
    KERNELS=="usb2"
    SUBSYSTEMS=="usb"
    DRIVERS=="usb"
    ATTRS{bDeviceSubClass}=="00"
    ATTRS{bDeviceProtocol}=="00"
    ATTRS{devpath}=="0"
    ATTRS{idVendor}=="1d6b"
    ATTRS{speed}=="480"
    ATTRS{bNumInterfaces}==" 1"
    ATTRS{bConfigurationValue}=="1"
    ATTRS{bMaxPacketSize0}=="64"
    ATTRS{authorized_default}=="1"
    ATTRS{busnum}=="2"
    ATTRS{devnum}=="1"
    ATTRS{configuration}==""
    ATTRS{bMaxPower}=="  0mA"
    ATTRS{authorized}=="1"
    ATTRS{bmAttributes}=="e0"
    ATTRS{bNumConfigurations}=="1"
    ATTRS{maxchild}=="2"
    ATTRS{bcdDevice}=="0305"
    ATTRS{avoid_reset_quirk}=="0"
    ATTRS{quirks}=="0x0"
    ATTRS{serial}=="0000:00:1d.0"
    ATTRS{version}==" 2.00"
    ATTRS{urbnum}=="24"
    ATTRS{manufacturer}=="Linux 3.5.0-46-generic ehci_hcd"
    ATTRS{removable}=="unknown"
    ATTRS{idProduct}=="0002"
    ATTRS{bDeviceClass}=="09"
    ATTRS{product}=="EHCI Host Controller"

  looking at parent device '/devices/pci0000:00/0000:00:1d.0':
    KERNELS=="0000:00:1d.0"
    SUBSYSTEMS=="pci"
    DRIVERS=="ehci_hcd"
    ATTRS{irq}=="23"
    ATTRS{subsystem_vendor}=="0x10cf"
    ATTRS{broken_parity_status}=="0"
    ATTRS{class}=="0x0c0320"
    ATTRS{companion}==""
    ATTRS{consistent_dma_mask_bits}=="32"
    ATTRS{dma_mask_bits}=="32"
    ATTRS{local_cpus}=="ff"
    ATTRS{device}=="0x1c26"
    ATTRS{uframe_periodic_max}=="100"
    ATTRS{enable}=="1"
    ATTRS{msi_bus}==""
    ATTRS{local_cpulist}=="0-7"
    ATTRS{vendor}=="0x8086"
    ATTRS{subsystem_device}=="0x160f"

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

root@se7en-LIFEBOOK-LH531:~#