Fixed yesterday :-)

A new RC3 is upcomming...

still the same error with new RC4 Version:

sudo nfc-poll 
nfc-poll uses libnfc libnfc-1.7.0-rc4
NFC reader: ACS / ACR122U PICC Interface opened
NFC device will poll during 30000 ms (20 pollings of 300 ms for 5 modulations)
error   libnfc.driver.acr122_usb    Too small reply
nfc_initiator_poll_target: Input / Output Error

I merged it with issue 217 which is re-opened.
See my recommendations in the other issue:
Please use only one of the two acr122 drivers, either acr122_usb (preferred) or 
acr122_pcsc.
If you use acr122_usb and have sometimes errors, better to stop pcscd or to 
remove acr122 from libccid detection list to avoid any conflict.

Please report your results and a full log trace if possible in the other issue, 
thanks!

the other issue was now closed, but my problem is still there. can we re-open 
this issue to get a fix of my problem?

cf comment #14 in issue 217  by romuald:

I think its possible to do some work to enable ACR122 polling in libnfc, but 
that's not a few minutes question...
I think this need to hack polling method to cut polling in 4 seconds long 
passes... Patches are welcome.

Please keep in mind that ACR122U is not a good device to be used with libnfc...

The front MCU prevents libnfc from using whole functions available on PN532 
chip.

hi, i have the same problem here:

StarK shm # nfc-list 
nfc-list uses libnfc libnfc-1.7.0-rc6-55-gdd20946
error   libnfc.driver.acr122_usb    Too small reply
nfc-list: ERROR: Unable to open NFC device: acr122_usb:004:002

and it's make the device make "beeps" while an nfc card is on it.

i use app-misc/acsccid-1.0.4 (from gentoo ~amd64 tree) (so i dont know how to 
remove acr122 from the detection list) , should i remove it totaly ?

For me, my touchatag reader stopped working with the "Too small reply" since 
git e49eb6c6600448f18f8bdcd0f59da85f04a3aa7f
I also bisected the svn archive, it breaks for me since svn 1328

On closer inspection, the problem with my reader is that it is recognized 
internally in the acr122_usb as an acr122, based on the USB vendor/product id. 
Once I force it to recognize as a touchatag (with a different escaping 
mechanism to communicate with the pn532), the reader works.

Please check latest commit as a few changes have been made.

With my devices all I get now is at rare occasions a failure at initialization 
and an automatic retry, which gives when opening the device:

error   libnfc.driver.acr122_usb    PN532 didn't reply
error   libnfc.driver.acr122_usb    PN532 init failed, trying again...
NFC reader: ACS / ACR122U PICC Interface opened

This happens very rarely, both for ACR122U and for Touchatag.
What's your experience?
Thanks for your feedback.

The acr122_usb now works for me with current git (as of 2013-6-15), thanks!

Thanks for the feedback.
I will close this bugreport.
Maybe some people will still get problems but anyways the faulty behavior will 
be quite different so better to open a new bugreport if needed.