• Registered: 2012-11-12
  • Posts: 3

Topic: [SOLVED] Why nfc-list only works with sudo using PN53x USB device ?

I downloaded, built, and installed libnfc-1.6.0-rc1 on Ubuntu 12.04 LTS.  All the utilities worked just fine.  i.e. I can do "nfc-list" to see the NFC reader and tag info.

Then I downloaded, built, and installed latest development tree of libnfc from yesterday (Nov 11).  In this case, nfc-list only works with sudo.  i.e. I have to do "sudo nfc-list" for it to show NFC reader and tag info.  If sudo is not used, it will always say "ERROR: Unable to open NFC device".

Anyone knows why this is happening?

Thanks

  • Registered: 2012-11-12
  • Posts: 3

Re: [SOLVED] Why nfc-list only works with sudo using PN53x USB device ?

With libnfc compiled with debug enabled, the following is seen when run without sudo:

debug    libnfc    allow_intrusive_scan is set to false
trace    libnfc.general    0 device(s) found using pn53x_usb driver
trace    libnfc.driver.acr122_usb    device found: Bus 003 Device 014 Name ACS ACR122
trace    libnfc.general    1 device(s) found using acr122_usb driver
trace    libnfc.driver.acr122_usb    3 element(s) have been decoded from "acr122_usb:003:014"
error     libnfc.driver.acr122_usb    Unable to claim USB interface (Operation not permitted)
trace    libnfc.general    Unable to open "acr122_usb:003:014".

How to fix the issue of "Unable to claim USB interface"?

Thanks

  • Registered: 2012-11-12
  • Posts: 3

Re: [SOLVED] Why nfc-list only works with sudo using PN53x USB device ?

I've copied the file "42-pn53x.rules" from libnfc/contrib/udev into /etc/udev/rules.d and the result is still the same.  Still need "sudo nfc-list" for it to work.

Anyone knows how to resolve this?

  • yobibe
  • Administrator
  • Offline
  • Registered: 2011-04-08
  • Posts: 142

Re: [SOLVED] Why nfc-list only works with sudo using PN53x USB device ?

42-pn53x.rules adds authorization for people in the group plugdev to access usb devices.
Did you add yourself to plugdev group?
When you add yourself to a group you also need to restart your login session.

Phil

yobibe's Website

  • Registered: 2012-11-04
  • Posts: 5

Re: [SOLVED] Why nfc-list only works with sudo using PN53x USB device ?

Hallo,

I had also almost the same issue. Maybe you can try the solution from http://www.libnfc.org/community/topic/6 … sets-conf/

1. create /etc/modprobe.d/blacklist-libnfc.conf that contains:
blacklist pn533
blacklist nfc
2. unplug device or restart Ubuntu

Thanks

  • rconty
  • Administrator
  • Offline
  • Registered: 2009-04-22
  • Posts: 926

Re: [SOLVED] Why nfc-list only works with sudo using PN53x USB device ?

Hello,

In the next release, the blacklist-libnfc.conf file will be provided in libnfc tarball:

https://code.google.com/p/libnfc/source … aa50e8ff02

Thanks!

Romuald Conty