How to fix acr122's and libnfc’s “Unable to claim USB interface” on Linux

If you like me have an acr122u usb NFC reader, you may see that issue when you connect it to the linux machine, run nfc-list and see something like this:

error   libnfc.driver.acr122_usb    Unable to claim USB interface (Permission denied)

Fortunately, it’s not very hard to fix:

1. sudo vim /etc/modprobe.d/blacklist-libnfc.conf
2. Add this line: blacklist pn533_usb
3. Reboot

Then try to read some cards:

sudo nfc-list -v

Enjoy your fully functional acr122u (: