udev rules error on BBB

Did you come up with that by yourself? Or did you have guidance from another source? i.e. did the device vendor provide you with that example and you just added the symlink on the end?

Mike

perform a

udevadm info /dev/ttyUSB0 

to check your values in your rule are correct.

Mike, VID&PID is belongs to my device, by the guidance on other sites that are referenced i came up, for command ls -l /dev/ttyUSB0 i found the device info is stored in /sys/dev/char/188.0, the result for above command is given bellow, are you telling my udev rules is not correct?

crwxrwxrwx 1 root dialout 188,  0  Feb 19 22:39 /dev/ttyUSB0

Hi Brian thanks, i checked my rule values with devadm info returns all are correct, i don't know why it is showing error unable to open device on '/sys/dev/ttyUSB0'

Do you get the error running udevadm test /dev/ttyUSB0 ?

Try  udevadm test  /sys/dev/char/188:0

Are you sure SUBSYSTEMS=="usb-serial" 

Usually they are "tty"

You can also check /var/log/syslog for errors that may be a clue.

I found my device SUBSYSTEM = "usb" , now it creates symlink at /etc/dev as expected, but my app is not able to open the device using symlink name

For e.g i used to open printer comport  as follows

/dev/printer   -  //dev/printer -> /dev/ttyUSB0

/dev/display  - //dev/display -> /dev/ttyUSB1

it says no such port, please share  how to use symlink name to open/close ports

ok so if you

ls -l /dev/printer

you get something like

lrwxrwxrwx 1 root root 7 Feb 20 09:19 /dev/printer -> ttyUSB0

you should be able to just use /dev/printer in just the same way you would use /dev/ttyUSB0

If you have something like minicom installed then

minicom -D /dev/printer

should open a terminal session with the port

please can you post the output for

udevadm info /dev/ttyUSB0

[root@hextek rules.d]# udevadm info -a -n /dev/ttyUSB0

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/pci0000:00/0000:00:1a.0/usb1/1-1/1-1.5/1-1.5.2/1-1.5.2:1.0/ttyUSB0/tty/ttyUSB0':

    KERNEL=="ttyUSB0"

    SUBSYSTEM=="tty"

    DRIVER==""

  looking at parent device '/devices/pci0000:00/0000:00:1a.0/usb1/1-1/1-1.5/1-1.5.2/1-1.5.2:1.0/ttyUSB0':

    KERNELS=="ttyUSB0"

    SUBSYSTEMS=="usb-serial"

    DRIVERS=="pl2303"

    ATTRS{port_number}=="0"

  looking at parent device '/devices/pci0000:00/0000:00:1a.0/usb1/1-1/1-1.5/1-1.5.2/1-1.5.2:1.0':

    KERNELS=="1-1.5.2:1.0"

    SUBSYSTEMS=="usb"

    DRIVERS=="pl2303"

    ATTRS{bInterfaceClass}=="ff"

    ATTRS{bInterfaceSubClass}=="00"

    ATTRS{bInterfaceProtocol}=="00"

    ATTRS{bNumEndpoints}=="03"

    ATTRS{supports_autosuspend}=="1"

    ATTRS{bAlternateSetting}==" 0"

    ATTRS{bInterfaceNumber}=="00"

  looking at parent device '/devices/pci0000:00/0000:00:1a.0/usb1/1-1/1-1.5/1-1.5.2':

    KERNELS=="1-1.5.2"

    SUBSYSTEMS=="usb"

    DRIVERS=="usb"

    ATTRS{bDeviceSubClass}=="00"

    ATTRS{bDeviceProtocol}=="00"

    ATTRS{devpath}=="1.5.2"

    ATTRS{idVendor}=="067b"

    ATTRS{speed}=="12"

    ATTRS{bNumInterfaces}==" 1"

    ATTRS{bConfigurationValue}=="1"

    ATTRS{bMaxPacketSize0}=="64"

    ATTRS{busnum}=="1"

    ATTRS{devnum}=="88"

    ATTRS{configuration}==""

    ATTRS{bMaxPower}=="100mA"

    ATTRS{authorized}=="1"

    ATTRS{bmAttributes}=="a0"

    ATTRS{bNumConfigurations}=="1"

    ATTRS{maxchild}=="0"

    ATTRS{bcdDevice}=="0300"

    ATTRS{avoid_reset_quirk}=="0"

    ATTRS{quirks}=="0x0"

    ATTRS{version}==" 1.10"

    ATTRS{urbnum}=="463"

    ATTRS{ltm_capable}=="no"

    ATTRS{manufacturer}=="Prolific Technology Inc."

    ATTRS{removable}=="unknown"

    ATTRS{idProduct}=="2303"

    ATTRS{bDeviceClass}=="00"

    ATTRS{product}=="USB-Serial Controller"

  looking at parent device '/devices/pci0000:00/0000:00:1a.0/usb1/1-1/1-1.5':

    KERNELS=="1-1.5"

    SUBSYSTEMS=="usb"

    DRIVERS=="usb"

    ATTRS{bDeviceSubClass}=="00"

    ATTRS{bDeviceProtocol}=="00"

    ATTRS{devpath}=="1.5"

    ATTRS{idVendor}=="058f"

    ATTRS{speed}=="12"

    ATTRS{bNumInterfaces}==" 1"

    ATTRS{bConfigurationValue}=="1"

    ATTRS{bMaxPacketSize0}=="8"

    ATTRS{busnum}=="1"

    ATTRS{devnum}=="84"

    ATTRS{configuration}==""

    ATTRS{bMaxPower}=="100mA"

    ATTRS{authorized}=="1"

    ATTRS{bmAttributes}=="e0"

    ATTRS{bNumConfigurations}=="1"

    ATTRS{maxchild}=="4"

    ATTRS{bcdDevice}=="0312"

    ATTRS{avoid_reset_quirk}=="0"

    ATTRS{quirks}=="0x2"

    ATTRS{version}==" 1.10"

    ATTRS{urbnum}=="136"

    ATTRS{ltm_capable}=="no"

    ATTRS{manufacturer}=="ALCOR"

    ATTRS{removable}=="removable"

    ATTRS{idProduct}=="9254"

    ATTRS{bDeviceClass}=="09"

    ATTRS{product}=="Generic USB Hub"

  looking at parent device '/devices/pci0000:00/0000:00:1a.0/usb1/1-1':

    KERNELS=="1-1"

    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}=="1"

    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}=="1932"

    ATTRS{ltm_capable}=="no"

    ATTRS{removable}=="fixed"

    ATTRS{idProduct}=="0020"

    ATTRS{bDeviceClass}=="09"

  looking at parent device '/devices/pci0000:00/0000:00:1a.0/usb1':

    KERNELS=="usb1"

    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}=="1"

    ATTRS{devnum}=="1"

    ATTRS{configuration}==""

    ATTRS{bMaxPower}=="0mA"

    ATTRS{authorized}=="1"

    ATTRS{bmAttributes}=="e0"

    ATTRS{bNumConfigurations}=="1"

    ATTRS{maxchild}=="3"

    ATTRS{bcdDevice}=="0309"

    ATTRS{avoid_reset_quirk}=="0"

    ATTRS{quirks}=="0x0"

    ATTRS{serial}=="0000:00:1a.0"

    ATTRS{version}==" 2.00"

    ATTRS{urbnum}=="267"

    ATTRS{ltm_capable}=="no"

    ATTRS{manufacturer}=="Linux 3.9.10-100.fc17.i686 ehci_hcd"

    ATTRS{removable}=="unknown"

    ATTRS{idProduct}=="0002"

    ATTRS{bDeviceClass}=="09"

    ATTRS{product}=="EHCI Host Controller"

  looking at parent device '/devices/pci0000:00/0000:00:1a.0':

    KERNELS=="0000:00:1a.0"

    SUBSYSTEMS=="pci"

    DRIVERS=="ehci-pci"

    ATTRS{irq}=="16"

    ATTRS{subsystem_vendor}=="0x8086"

    ATTRS{broken_parity_status}=="0"

    ATTRS{class}=="0x0c0320"

    ATTRS{companion}==""

    ATTRS{consistent_dma_mask_bits}=="32"

    ATTRS{dma_mask_bits}=="32"

    ATTRS{local_cpus}=="ffffffff"

    ATTRS{device}=="0x3b3c"

    ATTRS{uframe_periodic_max}=="100"

    ATTRS{enable}=="1"

    ATTRS{msi_bus}==""

    ATTRS{local_cpulist}=="0-31"

    ATTRS{vendor}=="0x8086"

    ATTRS{subsystem_device}=="0x0036"

    ATTRS{d3cold_allowed}=="1"

  looking at parent device '/devices/pci0000:00':

    KERNELS=="pci0000:00"

    SUBSYSTEMS==""

    DRIVERS==""

[root@hextek rules.d]#

Now i am able to open port using symlink name on my java app by using following line

       System.setProperty("gnu.io.rxtx.SerialPorts", "/dev/printer");

But according to rxtx lib source, it will omit other device if we user system property method, so that i can't use more than one device using it's symlink name,

is there any way to load more than one symlinked devices?

Reference

Trouble shooting - Rxtx

If you wish, you can set the system properties gnu.io.rxtx.SerialPorts and gnu.io.rxtx.ParallelPorts. If either of these is set, then no scanning will be carried out and only the specified ports will be available

Have a look at this it may help, it applies to  both RPi and BBB  http://angryelectron.com/rxtx-on-raspbian/