acr122 no reader found at 'usb'

I have an ACR122U-A9 too and got the same error.

Just for reference: I tried the ACR122U-A9 with the isbm-snep-java lib and it has compatibility issues. The version of ACR122U that works with this java lib is ACR122U-A2 (note for A2). I don't know if the A9 version has issues in nfcpy too or if I'm doing something wrong or missing some step as you, let's wait for another answer.

Exactly the same problem with the ACR122U-A9 here as well. It all works perfectly the the libnfc tools, but with nfcpy I get the exact same issue. Unfortunately I don't have another reader available to test against, so this is just a 'me too' post, I'm afraid.

This may now be solved with revision 204 and 205, please update and re-test. There was one issue with setting the USB device configuration - also my ACR122U203 didn't like that. A second issue I've found with activation when a card is already present.

For my device the initial log is as below and I'd be interested in similar snippets for the ACR122 version you have:

[main] enable debug output for module 'nfc.dev'
[nfc.clf] searching for reader with path 'usb'
[nfc.dev.transport] using pyusb version 0.x
[nfc.dev.transport] path matches '^(usb|)$'
[nfc.dev] trying usb:072f:2200
[nfc.dev] import nfc.dev.acr122
[nfc.dev.transport] >>> 6b050000000000000000ff00480000
[nfc.dev.transport] <<< 830a000000000000810041435231323255323033
[nfc.dev.acr122] GetFirmwareVersion called with timeout 100 ms
[nfc.dev.transport] >>> 6b070000000000000000ff00000002d402
[nfc.dev.transport] <<< 83080000000000008100d503320104079000
[nfc.dev.pn53x] chipset is a PN532 version 1.4

I'm afraid I'm still seeing the same issue here on Ubuntu 12.04 with the ACR122U-A9. This is what I get:

[nfc.clf] searching for reader with path 'usb'
[nfc.dev.transport] using pyusb version 0.x
[nfc.dev.transport] path matches '^(usb|)$'
[nfc.dev] trying usb:072f:2200
[nfc.dev] import nfc.dev.acr122
[nfc.dev.transport] >>> 6b050000000000000000ff00480000
-110
[nfc.clf] no reader found at 'usb'
[main] no contactless reader found

This is with the latest fetch with bzr. Happy to test any further changes! :)

Sorry for the late reply.
I'll try to test the new version asap.

In the meantime I also got what I needed working with a script called pyscar.

What I did was:
sudo apt-get install python-pyscard
sudo apt-get install pcscd

Took the code from:
http://pyscard.sourceforge.net/pyscard-usersguide.html#monitoringsmartcards

And that was enough to start reading rfid cards

Okay, a different response with revision 205 on this Raspberry Pi:

[main] enable debug output for module 'nfc'
[nfc.clf] searching for reader with path 'usb'
[nfc.dev.transport] using pyusb version 0.x
[nfc.dev.transport] path matches '^(usb|)$'
[nfc.dev] trying usb:072f:2200
[nfc.dev] import nfc.dev.acr122
[nfc.dev.transport] >>> 6b050000000000000000ff00480000
[nfc.dev.transport] <<< 830a000000000000810041435231323255323133
[nfc.dev.acr122] GetFirmwareVersion called with timeout 100 ms
[nfc.dev.transport] >>> 6b070000000000000000ff00000002d402
[nfc.dev.transport] <<< 830a000000000000810041435231323255323133
Traceback (most recent call last):
  File "examples/tagtool.py", line 439, in <module>
    TagTool().run()
  File "/home/pi/monday/nfcpy/examples/cli.py", line 283, in run
    while self.run_once() and self.options.loop:
  File "/home/pi/monday/nfcpy/examples/cli.py", line 230, in run_once
    try: clf = nfc.ContactlessFrontend(device)
  File "/home/pi/monday/nfcpy/nfc/clf.py", line 105, in __init__
    if path and not self.open(path):
  File "/home/pi/monday/nfcpy/nfc/clf.py", line 156, in open
    self.dev = nfc.dev.connect(path)
  File "/home/pi/monday/nfcpy/nfc/dev/__init__.py", line 64, in connect
    device = driver.init(usb)
  File "/home/pi/monday/nfcpy/nfc/dev/acr122.py", line 92, in init
    chipset = Chipset(transport)
  File "/home/pi/monday/nfcpy/nfc/dev/acr122.py", line 50, in __init__
    super(Chipset, self).__init__(transport)
  File "/home/pi/monday/nfcpy/nfc/dev/pn53x.py", line 126, in __init__
    ic, ver, rev, support = self.get_firmware_version()
  File "/home/pi/monday/nfcpy/nfc/dev/pn53x.py", line 243, in get_firmware_version
    else: ic, ver, rev, support = data
ValueError: too many values to unpack

A second try ended like this:

[main] enable debug output for module 'nfc'
[nfc.clf] searching for reader with path 'usb'
[nfc.dev.transport] using pyusb version 0.x
[nfc.dev.transport] path matches '^(usb|)$'
[nfc.dev] trying usb:072f:2200
[nfc.dev] import nfc.dev.acr122
[nfc.dev.transport] >>> 6b050000000000000000ff00480000
[nfc.dev.transport] <<< 83080000000000008100d503320106079000
[nfc.dev.acr122] failed to retrieve ACR122U version string
[nfc.clf] no reader found at 'usb'
[main] no contactless reader found

Looks like more of a USB problem. In the first execution the same answer is returned for two different commands, then in the second execution the answer to the first command is the one expected before. Very strange.

In general my impression of the RPi's USB implementation was so far very mixed. With libusb/pyusb 0.x it more or less never worked well. With libusb/pyusb 1.x it worked a lot better. Maybe you could switch to the pyusb 1.x?

I'm having this same issue - I think it is the same as bug https://bugs.launchpad.net/nfcpy/+bug/1257591 (I get this log output as well as the one in the bug *alternatingly*)

I now have an ACR122U-A9 and experience the same. Bug #1257591 will cover any progress.