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To Set Permission on USB Node "/Proc/Bus/Usb/bus-no/dev-no"

Discussion in 'Linux' started by Gurjeet Singh Batth, May 8, 2008.

  1. Gurjeet Singh Batth

    Gurjeet Singh Batth New Member

    Hi all,
    I am using CentOS 5 operating system. and trying to use a usb thermal printer.
    This Printer works well if I log in as a root user, but I want to use it in non-root user mode. I have put this non root user in lp group also.
    But No Success.

    My printer uses usb port listed under /proc/bus/usb/bus-no/dev-no directory tree.
    I want to set permission on it. [when I do it manually the printer starts working, but I don't want to do this in such way.] I need some automated way.

    Also I found some techniques to set rules and permissions on usb port. but those techniques set the permission for /dev/bus/usb/bus-no/dev-no. and are of no use for me.

    Please suggest me some good way to do so.
  2. aceqbaceq

    aceqbaceq New Member

    i had similar problem. fedora core 4. hp 1120 mfp. sane works only with root permissions.

    i used two files from packet iscan.

    first file

    /etc/hotplug/iscan-device , permissions = 755, root, root

    for script in $USB_SCRIPTS; do
        if [ -x $HOTPLUG_DIR/$TYPE/$script ]; then
     exec $HOTPLUG_DIR/$TYPE/$script
    # Activate fallback settings
    if [ "$ACTION" == add -a "$TYPE" == "usb" ]; then
        chmod $DEFAULT_PERMS "$DEVICE"

    second file

    /etc/hotplug/iscan.usermap , permissions = 644, root, root

    # Hewlett-Packard | HP LaserJet M1120 MFP
    iscan-device 0x0003 0x03f0 0x5617 0x0000 0x0000 0x00 0x00 0x00 0x00 0x00 0x00 0x00000000
    in the second file actually important and individual for you is 0x03f0= Vendor_Id and 0x5617=Device_Id.

    change it for yours. how determine?
    # sane-find-scanner

    what it does to me. it sets automatically permissions=666 to file

    /proc/bus/usb/bus-no/dev-no - this file concern my scanner when scanner plugged. :) and as i have permissions 666 then i can run


    as user. :)

    hope this help.

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