FAQ
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1. Compilation and installation was successful, but CUPS system for printer
notify on: 'Filter "rastertoezpl" for printer "..." not available: Permission
denied' or in state of printing jobs is: ".../rastertoezpl failed".
  - CUPS system doesn't have any access to the filter. Check mode of the path
    and of the rastertoezpl filter (read and execute for all). If you use
    security system (e.g. AppArmor, SELinux) check settings.

  - for AppArmor user
    If your system use AppArmor, check if the installed filter is accessible
    and executable from CUPS daemon over AppArmor setting. Or you can put
    AppArmor on CUPS to complain mode run
      $ sudo aa-complain /usr/sbin/cupsd
    and check if the problem is in setting of AppArmor. Edit AppArmor config
    file /etc/apparmor.d/usr.sbin.cupsd and line with permission for new filter
      "/usr/local/libexec/rastertoezpl/rastertoezpl Uxr,"
    add to section /usr/sbin/cupsd (of course, the path must be directed to the
    file, not to a symbolic link!).
    
    And then activate AppArmor with:
      $ sudo aa-enforce /usr/sbin/cupsd .


2. PPD files are installed, but not in CUPS menu.
  The PPD files are installed in a path through that CUPS doesn't walk. You can
  follow one of these actions:
  - Create symbolic link in a path that CUPS walked through to the installed
    directory with PPD files. (See parameters CREATE_PPDLINK and PPDLINK.)
  - During installation of the printer set the path of PPD files. (See
    parameter PPDDIR.)
  - Select PPD file manually.
