[fprint] AES2501 and async interface to libfprint

[Christian Schaubschlaeger]

Hello list,

I just tried to get my AES2501 working using libfprint's
async interface (I'm using version 0.1.0-pre1). Unfortunately
I failed. Here is what I tried:

fp_init();
discovered_devs = fp_discover_devs();
ddev = discovered_devs[0];
fp_async_dev_open(ddev,dev_open_cb,NULL);	// dev_open_cb initializes static s_fp_device
fp_async_enroll_start(s_fp_device,enroll_stage_cb,NULL);

None of these function calls return an error.
The problem is, that the callback function 'enroll_stage_cb'
never gets called; it seems, that fp_async_enroll_start does not
initiate scanning...

Am I doing something wrong?
Before I tried to use the synchronous interface to libfprint, which worked
fine!

Thanks in advance
Christian