[mythtv-users] Help understanding udev rules

Wed Apr 10 03:37:10 UTC 2013

Joe,

Thanks for the help.  The results of the rules is a symlink from /dev/v4l/hdpvr1 and /dev/v4l/hdpvr2 with lrwxrwxrwx  1 root root

myth_setup issues an error when I input /dev/v4l/hdpvr1 or 2 stating something like the device can not be probed.

jt at myth:/dev/v4l$ udevadm info -a -p $(udevadm info -q path -n /dev/video0)

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/pci0000:00/0000:00:12.2/usb1/1-2/1-2:1.0/video4linux/video0':
    KERNEL=="video0"
    SUBSYSTEM=="video4linux"
    DRIVER==""
    ATTR{name}=="Hauppauge HD PVR"
    ATTR{index}=="0"

  looking at parent device '/devices/pci0000:00/0000:00:12.2/usb1/1-2/1-2:1.0':
    KERNELS=="1-2:1.0"
    SUBSYSTEMS=="usb"
    DRIVERS=="hdpvr"
    ATTRS{bInterfaceNumber}=="00"
    ATTRS{bAlternateSetting}==" 0"
    ATTRS{bNumEndpoints}=="02"
    ATTRS{bInterfaceClass}=="ff"
    ATTRS{bInterfaceSubClass}=="02"
    ATTRS{bInterfaceProtocol}=="00"
    ATTRS{supports_autosuspend}=="0"

  looking at parent device '/devices/pci0000:00/0000:00:12.2/usb1/1-2':
    KERNELS=="1-2"
    SUBSYSTEMS=="usb"
    DRIVERS=="usb"
    ATTRS{configuration}==""
    ATTRS{bNumInterfaces}==" 1"
    ATTRS{bConfigurationValue}=="1"
    ATTRS{bmAttributes}=="c0"
    ATTRS{bMaxPower}=="  4mA"
    ATTRS{urbnum}=="618431"
    ATTRS{idVendor}=="2040"
    ATTRS{idProduct}=="4901"
    ATTRS{bcdDevice}=="0000"
    ATTRS{bDeviceClass}=="00"
    ATTRS{bDeviceSubClass}=="00"
    ATTRS{bDeviceProtocol}=="00"
    ATTRS{bNumConfigurations}=="1"
    ATTRS{bMaxPacketSize0}=="64"
    ATTRS{speed}=="480"
    ATTRS{busnum}=="1"
    ATTRS{devnum}=="2"
    ATTRS{devpath}=="2"
    ATTRS{version}==" 2.00"
    ATTRS{maxchild}=="0"
    ATTRS{quirks}=="0x0"
    ATTRS{avoid_reset_quirk}=="0"
    ATTRS{authorized}=="1"
    ATTRS{manufacturer}=="AMBA"
    ATTRS{product}=="Hauppauge HD PVR"
    ATTRS{serial}=="00A29AC2"

  looking at parent device '/devices/pci0000:00/0000:00:12.2/usb1':
    KERNELS=="usb1"
    SUBSYSTEMS=="usb"
    DRIVERS=="usb"
    ATTRS{configuration}==""
    ATTRS{bNumInterfaces}==" 1"
    ATTRS{bConfigurationValue}=="1"
    ATTRS{bmAttributes}=="e0"
    ATTRS{bMaxPower}=="  0mA"
    ATTRS{urbnum}=="66"
    ATTRS{idVendor}=="1d6b"
    ATTRS{idProduct}=="0002"
    ATTRS{bcdDevice}=="0302"
    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}=="6"
    ATTRS{quirks}=="0x0"
    ATTRS{avoid_reset_quirk}=="0"
    ATTRS{authorized}=="1"
    ATTRS{manufacturer}=="Linux 3.2.0-23-generic ehci_hcd"
    ATTRS{product}=="EHCI Host Controller"
    ATTRS{serial}=="0000:00:12.2"
    ATTRS{authorized_default}=="1"

  looking at parent device '/devices/pci0000:00/0000:00:12.2':
    KERNELS=="0000:00:12.2"
    SUBSYSTEMS=="pci"
    DRIVERS=="ehci_hcd"
    ATTRS{vendor}=="0x1002"
    ATTRS{device}=="0x4396"
    ATTRS{subsystem_vendor}=="0x1043"
    ATTRS{subsystem_device}=="0x82ef"
    ATTRS{class}=="0x0c0320"
    ATTRS{irq}=="17"
    ATTRS{local_cpus}=="00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000003"
    ATTRS{local_cpulist}=="0-1"
    ATTRS{numa_node}=="0"
    ATTRS{dma_mask_bits}=="32"
    ATTRS{consistent_dma_mask_bits}=="32"
    ATTRS{broken_parity_status}=="0"
    ATTRS{msi_bus}==""
    ATTRS{companion}==""
    ATTRS{uframe_periodic_max}=="100"

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

jt at myth:/dev/v4l$ udevadm info -a -p $(udevadm info -q path -n /dev/video1)

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/pci0000:00/0000:00:12.2/usb1/1-5/1-5:1.0/video4linux/video1':
    KERNEL=="video1"
    SUBSYSTEM=="video4linux"
    DRIVER==""
    ATTR{name}=="Hauppauge HD PVR"
    ATTR{index}=="0"

  looking at parent device '/devices/pci0000:00/0000:00:12.2/usb1/1-5/1-5:1.0':
    KERNELS=="1-5:1.0"
    SUBSYSTEMS=="usb"
    DRIVERS=="hdpvr"
    ATTRS{bInterfaceNumber}=="00"
    ATTRS{bAlternateSetting}==" 0"
    ATTRS{bNumEndpoints}=="02"
    ATTRS{bInterfaceClass}=="ff"
    ATTRS{bInterfaceSubClass}=="02"
    ATTRS{bInterfaceProtocol}=="00"
    ATTRS{supports_autosuspend}=="0"

  looking at parent device '/devices/pci0000:00/0000:00:12.2/usb1/1-5':
    KERNELS=="1-5"
    SUBSYSTEMS=="usb"
    DRIVERS=="usb"
    ATTRS{configuration}==""
    ATTRS{bNumInterfaces}==" 1"
    ATTRS{bConfigurationValue}=="1"
    ATTRS{bmAttributes}=="c0"
    ATTRS{bMaxPower}=="  4mA"
    ATTRS{urbnum}=="9960"
    ATTRS{idVendor}=="2040"
    ATTRS{idProduct}=="4900"
    ATTRS{bcdDevice}=="0000"
    ATTRS{bDeviceClass}=="00"
    ATTRS{bDeviceSubClass}=="00"
    ATTRS{bDeviceProtocol}=="00"
    ATTRS{bNumConfigurations}=="1"
    ATTRS{bMaxPacketSize0}=="64"
    ATTRS{speed}=="480"
    ATTRS{busnum}=="1"
    ATTRS{devnum}=="3"
    ATTRS{devpath}=="5"
    ATTRS{version}==" 2.00"
    ATTRS{maxchild}=="0"
    ATTRS{quirks}=="0x0"
    ATTRS{avoid_reset_quirk}=="0"
    ATTRS{authorized}=="1"
    ATTRS{manufacturer}=="AMBA"
    ATTRS{product}=="Hauppauge HD PVR"
    ATTRS{serial}=="00A252CB"

  looking at parent device '/devices/pci0000:00/0000:00:12.2/usb1':
    KERNELS=="usb1"
    SUBSYSTEMS=="usb"
    DRIVERS=="usb"
    ATTRS{configuration}==""
    ATTRS{bNumInterfaces}==" 1"
    ATTRS{bConfigurationValue}=="1"
    ATTRS{bmAttributes}=="e0"
    ATTRS{bMaxPower}=="  0mA"
    ATTRS{urbnum}=="66"
    ATTRS{idVendor}=="1d6b"
    ATTRS{idProduct}=="0002"
    ATTRS{bcdDevice}=="0302"
    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}=="6"
    ATTRS{quirks}=="0x0"
    ATTRS{avoid_reset_quirk}=="0"
    ATTRS{authorized}=="1"
    ATTRS{manufacturer}=="Linux 3.2.0-23-generic ehci_hcd"
    ATTRS{product}=="EHCI Host Controller"
    ATTRS{serial}=="0000:00:12.2"
    ATTRS{authorized_default}=="1"

  looking at parent device '/devices/pci0000:00/0000:00:12.2':
    KERNELS=="0000:00:12.2"
    SUBSYSTEMS=="pci"
    DRIVERS=="ehci_hcd"
    ATTRS{vendor}=="0x1002"
    ATTRS{device}=="0x4396"
    ATTRS{subsystem_vendor}=="0x1043"
    ATTRS{subsystem_device}=="0x82ef"
    ATTRS{class}=="0x0c0320"
    ATTRS{irq}=="17"
    ATTRS{local_cpus}=="00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000003"
    ATTRS{local_cpulist}=="0-1"
    ATTRS{numa_node}=="0"
    ATTRS{dma_mask_bits}=="32"
    ATTRS{consistent_dma_mask_bits}=="32"
    ATTRS{broken_parity_status}=="0"
    ATTRS{msi_bus}==""
    ATTRS{companion}==""
    ATTRS{uframe_periodic_max}=="100"

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

I'm running Ubuntu12.04 Mythtv .26+fixes

The HDPVRs are mapped to the correct /dev/video's but I'm not sure that they will stay that way.

I hope this info helps.

thanks,

adios,
jt

On Apr 9, 2013, at 9:02 AM, Joe Henley wrote:

>> I read the mythtv wiki page (http://www.mythtv.org/wiki/Device_Filenames_and_udev) and copied the HD PVR sample substituting the serial numbers in the sample for my serial numbers. My confusion comes from my assumption that I would point to the SYMLINK device vs /dev/video0/1. mythtv_setup doesn't like the SYMLINK (/dev/v4l/hdpvr1/2) but /dev/video0 and /dev/video1 work.
> I use this approach in my Myth setup and it works fine; so it's possible.
> 
> It's hard to pinpoint the issue you have, we'd need to see the permissions you've set and the output of
> "udevadm info -a -p $(udevadm info -q path -n /dev/video0" or equivalent.   That being said....
> 
> Do you have your permissions set properly?  I usually include
> ..., SYMLINK+="<yada yada>", MODE="0777",OWNER="root",GROUP="root"
> on the end of my rule entries. Also, I don't know if it matters, but I just noticed that I do not create the symlink inside /dev/v4l.  I create it within /dev.  So my <yada yada> above is like "HDPVR_1", not "v4l/HDPVR_1"
> 
> What OS are you using?  My BE runs Fedora Core 16, with that g@@awful systemd thing, so I also include in my rules entries
> SUBSYSTEM=="video4linux", ATTR{name}=="Hauppauge HD PVR", TAG+="systemd"
> 
> From my experience, you are correct (in your assumption) to "point to the SYMLINK device."  My guess is that  the problem is elsewhere (eg., permissions,  tags, etc.).
> 
> Good luck, and let us know how you do with this.
> 
> Joe Henley
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