Topic: libnfc.driver.acr122_usb -> "Invalid RDR_to_PC_DataBlock frame"

I have a USB hub connected to a RPi that connect to 3 ACR122U readers:

pi@raspberrypi ~ $ lsusb
Bus 001 Device 002: ID 0424:9512 Standard Microsystems Corp. 
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 003: ID 0424:ec00 Standard Microsystems Corp. 
Bus 001 Device 004: ID 0bda:8176 Realtek Semiconductor Corp. RTL8188CUS 802.11n WLAN Adapter
Bus 001 Device 005: ID 05e3:0610 Genesys Logic, Inc. 4-port hub
Bus 001 Device 006: ID 072f:2200 Advanced Card Systems, Ltd 
Bus 001 Device 007: ID 072f:2200 Advanced Card Systems, Ltd 
Bus 001 Device 008: ID 072f:2200 Advanced Card Systems, Ltd 

I get the following error when I try to nfc-list:

pi@raspberrypi ~ $ sudo nfc-list
nfc-list uses libnfc libnfc-1.7.1
NFC device: ACS / ACR122U PICC Interface opened
error    libnfc.driver.acr122_usb    Invalid RDR_to_PC_DataBlock frame
error    libnfc.driver.acr122_usb    PN532 init failed, trying again...
error    libnfc.driver.acr122_usb    Invalid RDR_to_PC_DataBlock frame
error    libnfc.driver.acr122_usb    PN532 init failed, trying again...
error    libnfc.driver.acr122_usb    Invalid RDR_to_PC_DataBlock frame
nfc-list: ERROR: Unable to open NFC device: acr122_usb:001:007
NFC device: ACS / ACR122U PICC Interface opened

The error seems random:

* Some times is happens as described above,
* Some times it doesn't show up at all, and
* Some times lsusb doesn't locate one of the readers at all, and I have to unplug and plug back in all of them

I'm baffled at how random this looks sad I just tried again and I get 2 readers with errors:

pi@raspberrypi ~ $ sudo nfc-list
nfc-list uses libnfc libnfc-1.7.1
error    libnfc.driver.acr122_usb    Invalid RDR_to_PC_DataBlock frame
error    libnfc.driver.acr122_usb    PN532 init failed, trying again...
error    libnfc.driver.acr122_usb    Invalid RDR_to_PC_DataBlock frame
error    libnfc.driver.acr122_usb    PN532 init failed, trying again...
error    libnfc.driver.acr122_usb    Invalid RDR_to_PC_DataBlock frame
nfc-list: ERROR: Unable to open NFC device: acr122_usb:001:014
error    libnfc.driver.acr122_usb    Invalid RDR_to_PC_DataBlock frame
error    libnfc.driver.acr122_usb    PN532 init failed, trying again...
error    libnfc.driver.acr122_usb    Invalid RDR_to_PC_DataBlock frame
error    libnfc.driver.acr122_usb    PN532 init failed, trying again...
error    libnfc.driver.acr122_usb    Invalid RDR_to_PC_DataBlock frame
nfc-list: ERROR: Unable to open NFC device: acr122_usb:001:013
NFC device: ACS / ACR122U PICC Interface opened

Is there a way to debug this?

Re: libnfc.driver.acr122_usb -> "Invalid RDR_to_PC_DataBlock frame"

Hello,

First, I think you already know that ACR122 is a bad choice and is bogus and I assume you know what you are doing smile
Please read README file, wiki and forum posts before posting...

Next, you should NEVER run libnfc's tool as root...
Please read README file, wiki and forum posts before putting some "sudo"...

Is there a way to debug this?

Please read README file, wiki and forum posts before asking trivial questions...

So, maybe you have real bug... but please RTFM smile

Enjoy!

Romuald Conty