[opensuse] udev -- what is this doing?

4 Jun 2009

      I'm trying to solve a persistent video device naming problem having to
do with myth, it requires the /dev/video? to be consistent on each
startup.  I have what looks like a solution but do not understand
exactly what it means, can anyone who understands udev shed some light
on what this is doing and how it's doing it?

solution :
/etc/udev/rules.d/51-setup-video
KERNEL=="video[0-9]*",ATTR{name}=="ivtv0 encoder
MPG",DRIVERS=="ivtv",NAME="video0"

KERNEL=="video[0-9]*",ATTR{name}=="gspca main
drive",DRIVERS=="usb",NAME="video1"

  Those are two lines split by evolution, they are derived by the
following generated info:

Udevinfo 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/pci0000:00/0000:00:08.0/0000:01:08.0/video4linux/video0':
    KERNEL=="video0"
    SUBSYSTEM=="video4linux"
    DRIVER==""
    ATTR{name}=="ivtv0 encoder MPG"
    ATTR{index}=="0"

  looking at parent device
'/devices/pci0000:00/0000:00:08.0/0000:01:08.0':
    KERNELS=="0000:01:08.0"
    SUBSYSTEMS=="pci"
    DRIVERS=="ivtv"
    ATTRS{vendor}=="0x4444"
    ATTRS{device}=="0x0016"
    ATTRS{subsystem_vendor}=="0x0070"
    ATTRS{subsystem_device}=="0x8003"
    ATTRS{class}=="0x040000"
    ATTRS{irq}=="16"
    ATTRS{local_cpus}=="00000000,00000000,00000000,00000001"
    ATTRS{local_cpulist}=="0"

ATTRS{modalias}=="pci:v00004444d00000016sv00000070sd00008003bc04sc00i00"
    ATTRS{numa_node}=="0"
    ATTRS{enable}=="1"
    ATTRS{broken_parity_status}=="0"
    ATTRS{msi_bus}==""

  looking at parent device '/devices/pci0000:00/0000:00:08.0':
    KERNELS=="0000:00:08.0"
    SUBSYSTEMS=="pci"
    DRIVERS==""
    ATTRS{vendor}=="0x10de"
    ATTRS{device}=="0x006c"
    ATTRS{subsystem_vendor}=="0x0000"
    ATTRS{subsystem_device}=="0x0000"
    ATTRS{class}=="0x060400"
    ATTRS{irq}=="0"
    ATTRS{local_cpus}=="00000000,00000000,00000000,00000001"
    ATTRS{local_cpulist}=="0"

ATTRS{modalias}=="pci:v000010DEd0000006Csv00000000sd00000000bc06sc04i00"
    ATTRS{numa_node}=="0"
    ATTRS{enable}=="1"
    ATTRS{broken_parity_status}=="0"
    ATTRS{msi_bus}=="1"

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

and:

Udevinfo 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/pci0000:00/0000:00:02.2/usb1/1-5/1-5.2/video4linux/video1':
    KERNEL=="video1"
    SUBSYSTEM=="video4linux"
    DRIVER==""
    ATTR{name}=="gspca main driver"
    ATTR{index}=="0"

  looking at parent device
'/devices/pci0000:00/0000:00:02.2/usb1/1-5/1-5.2':
    KERNELS=="1-5.2"
    SUBSYSTEMS=="usb"
    DRIVERS=="usb"
    ATTRS{configuration}==""
    ATTRS{bNumInterfaces}==" 3"
    ATTRS{bConfigurationValue}=="1"
    ATTRS{bmAttributes}=="a0"
    ATTRS{bMaxPower}=="100mA"
    ATTRS{urbnum}=="1218"
    ATTRS{idVendor}=="046d"
    ATTRS{idProduct}=="08d7"
    ATTRS{bcdDevice}=="0100"
    ATTRS{bDeviceClass}=="00"
    ATTRS{bDeviceSubClass}=="00"
    ATTRS{bDeviceProtocol}=="00"
    ATTRS{bNumConfigurations}=="1"
    ATTRS{bMaxPacketSize0}=="8"
    ATTRS{speed}=="12"
    ATTRS{busnum}=="1"
    ATTRS{devnum}=="4"
    ATTRS{version}==" 1.10"
    ATTRS{maxchild}=="0"
    ATTRS{quirks}=="0x0"
    ATTRS{authorized}=="1"

  looking at parent device '/devices/pci0000:00/0000:00:02.2/usb1/1-5':
    KERNELS=="1-5"
    SUBSYSTEMS=="usb"
    DRIVERS=="usb"
    ATTRS{configuration}==""
    ATTRS{bNumInterfaces}==" 1"
    ATTRS{bConfigurationValue}=="1"
    ATTRS{bmAttributes}=="e0"
    ATTRS{bMaxPower}=="  2mA"
    ATTRS{urbnum}=="74"
    ATTRS{idVendor}=="050d"
    ATTRS{idProduct}=="0416"
    ATTRS{bcdDevice}=="0000"
    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{version}==" 2.00"
    ATTRS{maxchild}=="7"
    ATTRS{quirks}=="0x0"
    ATTRS{authorized}=="1"

  looking at parent device '/devices/pci0000:00/0000:00:02.2/usb1':
    KERNELS=="usb1"
    SUBSYSTEMS=="usb"
    DRIVERS=="usb"
    ATTRS{configuration}==""
    ATTRS{bNumInterfaces}==" 1"
    ATTRS{bConfigurationValue}=="1"
    ATTRS{bmAttributes}=="e0"
    ATTRS{bMaxPower}=="  0mA"
    ATTRS{urbnum}=="48"
    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{version}==" 2.00"
    ATTRS{maxchild}=="6"
    ATTRS{quirks}=="0x0"
    ATTRS{authorized}=="1"
    ATTRS{manufacturer}=="Linux 2.6.27.21-0.1-pae ehci_hcd"
    ATTRS{product}=="EHCI Host Controller"
    ATTRS{serial}=="0000:00:02.2"
    ATTRS{authorized_default}=="1"

  looking at parent device '/devices/pci0000:00/0000:00:02.2':
    KERNELS=="0000:00:02.2"
    SUBSYSTEMS=="pci"
    DRIVERS=="ehci_hcd"
    ATTRS{vendor}=="0x10de"
    ATTRS{device}=="0x0068"
    ATTRS{subsystem_vendor}=="0x1458"
    ATTRS{subsystem_device}=="0x5004"
    ATTRS{class}=="0x0c0320"
    ATTRS{irq}=="22"
    ATTRS{local_cpus}=="00000000,00000000,00000000,00000001"
    ATTRS{local_cpulist}=="0"

ATTRS{modalias}=="pci:v000010DEd00000068sv00001458sd00005004bc0Csc03i20"
    ATTRS{numa_node}=="0"
    ATTRS{enable}=="1"
    ATTRS{broken_parity_status}=="0"
    ATTRS{msi_bus}==""

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

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[opensuse] udev -- what is this doing?

Mike McMullin