[fprint] Error in developement of UPEK 2020 driver derived by upekts.c

[Andrea Oliveri]

Hello,
sorry for my english but im italian..
 i try to develop a libfprint driver for upek TCS5D
fingerprint reader/coprocessor that is installed in my lenovo thinkpad
T430.
I discover that if i change the vendor/product id of UPEK TouchStrip
driver (upekts.c) the reader is recognized by
library but doesnt read. So i have sniffed usb packets among proprietary
library under windows and the device and i found initialization
sequences.
I have tryed to substitute my initialization sequences in the driver,
and i added two new state in the list of finite state machine but, when
i have defined a new read state i have recieved an error from libusb:
the host sent a request of data to device but device replied with a
EIOERROR (-121). I have compared the sniffed packets onto linux and
windows and there are identical (the only different is the lenght of
request bulk data from host to device, in  driver it is smaller than
in the proprietary library).
Please can you help me? i dont know if it is a bug in modified
driver version, hardware failure (i have a usb3 controller...but under
windows XP the device works correctly) or other...

Thank you

Andrea