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/pci0000:00/0000:00:02.0/usb2/2-7/2-7:1.0/host12/target12:0:0/12:0:0:0/block/sdh/sdh1':
    KERNEL=="sdh1"
    SUBSYSTEM=="block"
    DRIVER==""
    ATTR{partition}=="1"
    ATTR{start}=="44"
    ATTR{size}=="15679396"
    ATTR{ro}=="0"
    ATTR{alignment_offset}=="0"
    ATTR{discard_alignment}=="4294944768"
    ATTR{stat}=="      83     2842     3257     3316        0        0        0        0        0     1980     3316"
    ATTR{inflight}=="       0        0"

  looking at parent device '/devices/pci0000:00/0000:00:02.0/usb2/2-7/2-7:1.0/host12/target12:0:0/12:0:0:0/block/sdh':
    KERNELS=="sdh"
    SUBSYSTEMS=="block"
    DRIVERS==""
    ATTRS{range}=="16"
    ATTRS{ext_range}=="256"
    ATTRS{removable}=="1"
    ATTRS{ro}=="0"
    ATTRS{size}=="15794175"
    ATTRS{alignment_offset}=="0"
    ATTRS{discard_alignment}=="0"
    ATTRS{capability}=="51"
    ATTRS{stat}=="      98     2946     3376     3528        0        0        0        0        0     2192     3528"
    ATTRS{inflight}=="       0        0"
    ATTRS{events}=="media_change"
    ATTRS{events_async}==""
    ATTRS{events_poll_msecs}=="-1"

  looking at parent device '/devices/pci0000:00/0000:00:02.0/usb2/2-7/2-7:1.0/host12/target12:0:0/12:0:0:0':
    KERNELS=="12:0:0:0"
    SUBSYSTEMS=="scsi"
    DRIVERS=="sd"
    ATTRS{device_blocked}=="0"
    ATTRS{type}=="0"
    ATTRS{scsi_level}=="0"
    ATTRS{vendor}=="SanDisk "
    ATTRS{model}=="Cruzer          "
    ATTRS{rev}=="7.01"
    ATTRS{state}=="running"
    ATTRS{timeout}=="30"
    ATTRS{iocounterbits}=="32"
    ATTRS{iorequest_cnt}=="0x9c"
    ATTRS{iodone_cnt}=="0x9c"
    ATTRS{ioerr_cnt}=="0x1"
    ATTRS{evt_media_change}=="0"
    ATTRS{dh_state}=="detached"
    ATTRS{queue_depth}=="1"
    ATTRS{queue_type}=="none"
    ATTRS{max_sectors}=="240"

  looking at parent device '/devices/pci0000:00/0000:00:02.0/usb2/2-7/2-7:1.0/host12/target12:0:0':
    KERNELS=="target12:0:0"
    SUBSYSTEMS=="scsi"
    DRIVERS==""

  looking at parent device '/devices/pci0000:00/0000:00:02.0/usb2/2-7/2-7:1.0/host12':
    KERNELS=="host12"
    SUBSYSTEMS=="scsi"
    DRIVERS==""

  looking at parent device '/devices/pci0000:00/0000:00:02.0/usb2/2-7/2-7:1.0':
    KERNELS=="2-7:1.0"
    SUBSYSTEMS=="usb"
    DRIVERS=="usb-storage"
    ATTRS{bInterfaceNumber}=="00"
    ATTRS{bAlternateSetting}==" 0"
    ATTRS{bNumEndpoints}=="02"
    ATTRS{bInterfaceClass}=="08"
    ATTRS{bInterfaceSubClass}=="06"
    ATTRS{bInterfaceProtocol}=="50"
    ATTRS{supports_autosuspend}=="1"

  looking at parent device '/devices/pci0000:00/0000:00:02.0/usb2/2-7':
    KERNELS=="2-7"
    SUBSYSTEMS=="usb"
    DRIVERS=="usb"
    ATTRS{configuration}==""
    ATTRS{bNumInterfaces}==" 1"
    ATTRS{bConfigurationValue}=="1"
    ATTRS{bmAttributes}=="80"
    ATTRS{bMaxPower}=="100mA"
    ATTRS{urbnum}=="793"
    ATTRS{idVendor}=="0781"
    ATTRS{idProduct}=="5151"
    ATTRS{bcdDevice}=="0200"
    ATTRS{bDeviceClass}=="00"
    ATTRS{bDeviceSubClass}=="00"
    ATTRS{bDeviceProtocol}=="00"
    ATTRS{bNumConfigurations}=="1"
    ATTRS{bMaxPacketSize0}=="64"
    ATTRS{speed}=="12"
    ATTRS{busnum}=="2"
    ATTRS{devnum}=="4"
    ATTRS{devpath}=="7"
    ATTRS{version}==" 2.00"
    ATTRS{maxchild}=="0"
    ATTRS{quirks}=="0x0"
    ATTRS{avoid_reset_quirk}=="0"
    ATTRS{authorized}=="1"
    ATTRS{manufacturer}=="SanDisk"
    ATTRS{product}=="Cruzer Micro"
    ATTRS{serial}=="2845331181C0D883"

  looking at parent device '/devices/pci0000:00/0000:00:02.0/usb2':
    KERNELS=="usb2"
    SUBSYSTEMS=="usb"
    DRIVERS=="usb"
    ATTRS{configuration}==""
    ATTRS{bNumInterfaces}==" 1"
    ATTRS{bConfigurationValue}=="1"
    ATTRS{bmAttributes}=="e0"
    ATTRS{bMaxPower}=="  0mA"
    ATTRS{urbnum}=="136"
    ATTRS{idVendor}=="1d6b"
    ATTRS{idProduct}=="0001"
    ATTRS{bcdDevice}=="0206"
    ATTRS{bDeviceClass}=="09"
    ATTRS{bDeviceSubClass}=="00"
    ATTRS{bDeviceProtocol}=="00"
    ATTRS{bNumConfigurations}=="1"
    ATTRS{bMaxPacketSize0}=="64"
    ATTRS{speed}=="12"
    ATTRS{busnum}=="2"
    ATTRS{devnum}=="1"
    ATTRS{devpath}=="0"
    ATTRS{version}==" 1.10"
    ATTRS{maxchild}=="8"
    ATTRS{quirks}=="0x0"
    ATTRS{avoid_reset_quirk}=="0"
    ATTRS{authorized}=="1"
    ATTRS{manufacturer}=="Linux 2.6.38-8-generic ohci_hcd"
    ATTRS{product}=="OHCI Host Controller"
    ATTRS{serial}=="0000:00:02.0"
    ATTRS{authorized_default}=="1"

  looking at parent device '/devices/pci0000:00/0000:00:02.0':
    KERNELS=="0000:00:02.0"
    SUBSYSTEMS=="pci"
    DRIVERS=="ohci_hcd"
    ATTRS{vendor}=="0x10de"
    ATTRS{device}=="0x005a"
    ATTRS{subsystem_vendor}=="0x1043"
    ATTRS{subsystem_device}=="0x815a"
    ATTRS{class}=="0x0c0310"
    ATTRS{irq}=="20"
    ATTRS{local_cpus}=="ff"
    ATTRS{local_cpulist}=="0-7"
    ATTRS{dma_mask_bits}=="32"
    ATTRS{consistent_dma_mask_bits}=="32"
    ATTRS{broken_parity_status}=="0"
    ATTRS{msi_bus}==""

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