[fprint] USB ID 04f3:0903 "Elan Microelectronics Corp."

[Sébastien Béchet]

As you ask, i tried [these 
changes](https://github.com/sbechet/libfprint/commit/dd5275f8dcdc24e8d94a3b936516c4242d8bf008) 
for a first try with `--enable-debug-log` in configure.

```
$ fprintd-list sbechet
found 1 devices
Device at /net/reactivated/Fprint/Device/0
Using device /net/reactivated/Fprint/Device/0
User sbechet has no fingers enrolled for ElanTech Fingerprint Sensor.
```

`journalctl -f` said:


```
nov. 09 17:23:09 mycomputer dbus-daemon[283]: [system] Activating via 
systemd: service name='net.reactivated.Fprint' unit='fprintd.service' 
requested by ':1.233' (uid=1000 pid=2305 comm="fprintd-list sbechet ")
nov. 09 17:23:09 mycomputer fprintd[2306]: fp:debug [fp_init]
[...]
nov. 09 17:23:09 mycomputer fprintd[2306]: fp:debug [register_driver] 
registered driver elan
nov. 09 17:23:09 mycomputer fprintd[2306]: fp:debug 
[find_supporting_driver] driver elan supports USB device 04f3:0903
nov. 09 17:23:09 mycomputer fprintd[2306]: fp:debug 
[find_supporting_driver] selected driver elan supports USB device 
04f3:0903
```

Then I try enrollement:

```
$ fprintd-enroll
Using device /net/reactivated/Fprint/Device/0
Enrolling right-index-finger finger.
Enroll result: enroll-disconnected
```

journalctl:

```
nov. 09 17:27:35 mycomputer fprintd[2379]: user 'sbechet' claiming the 
device: 0
nov. 09 17:27:35 mycomputer fprintd[2379]: async:debug 
[fp_async_dev_open]
nov. 09 17:27:35 mycomputer fprintd[2379]: now monitoring fd 15
nov. 09 17:27:35 mycomputer fprintd[2379]: device 0 claim status 0
nov. 09 17:27:35 mycomputer fprintd[2379]: elan:debug [dev_init]
nov. 09 17:27:35 mycomputer fprintd[2379]: async:debug 
[fpi_drvcb_open_complete] status 0
nov. 09 17:27:35 mycomputer fprintd[2379]: start enrollment device 0 
finger 7
nov. 09 17:27:35 mycomputer fprintd[2379]: async:debug 
[fp_async_enroll_start] starting enrollment
nov. 09 17:27:35 mycomputer fprintd[2379]: fp:debug 
[generic_acquire_start] action 1
nov. 09 17:27:35 mycomputer fprintd[2379]: elan:debug [dev_activate]
nov. 09 17:27:35 mycomputer fprintd[2379]: elan:debug [elan_dev_reset]
nov. 09 17:27:35 mycomputer fprintd[2379]: drv:debug 
[__ssm_call_handler] 0x55f20425fb70 entering state 0
nov. 09 17:27:35 mycomputer fprintd[2379]: elan:debug [elan_run_cmds]
nov. 09 17:27:35 mycomputer fprintd[2379]: elan:debug 
[elan_run_next_cmd]
nov. 09 17:27:35 mycomputer fprintd[2379]: elan:debug [elan_cmd_cb]
nov. 09 17:27:35 mycomputer fprintd[2379]: elan:debug [elan_cmd_read]
nov. 09 17:27:35 mycomputer fprintd[2379]: elan:debug [elan_cmd_cb]
nov. 09 17:27:35 mycomputer fprintd[2379]: elan:debug [elan_cmd_done]
nov. 09 17:27:35 mycomputer fprintd[2379]: elan:debug 
[elan_run_next_cmd]
nov. 09 17:27:35 mycomputer fprintd[2379]: elan:debug [elan_cmd_cb]
nov. 09 17:27:35 mycomputer fprintd[2379]: elan:debug [elan_cmd_read]
nov. 09 17:27:35 mycomputer fprintd[2379]: elan:debug [elan_cmd_cb]
nov. 09 17:27:35 mycomputer fprintd[2379]: elan:debug [elan_cmd_done]
nov. 09 17:27:35 mycomputer fprintd[2379]: elan:debug 
[elan_run_next_cmd]
nov. 09 17:27:35 mycomputer fprintd[2379]: elan:debug [elan_cmd_cb]
nov. 09 17:27:35 mycomputer fprintd[2379]: elan:debug [elan_cmd_read]
nov. 09 17:27:35 mycomputer fprintd[2379]: elan:debug [elan_cmd_cb]
nov. 09 17:27:35 mycomputer fprintd[2379]: elan:debug [elan_cmd_cb] 
unexpected transfer length
nov. 09 17:27:35 mycomputer fprintd[2379]: drv:debug 
[fpi_ssm_mark_aborted] error -71 from state 0
nov. 09 17:27:35 mycomputer fprintd[2379]: drv:debug 
[fpi_ssm_mark_completed] 0x55f20425fb70 completed with status -71
nov. 09 17:27:35 mycomputer fprintd[2379]: elan:debug [init_complete]
nov. 09 17:27:35 mycomputer fprintd[2379]: fp:debug 
[fpi_imgdev_session_error] error -71
nov. 09 17:27:35 mycomputer fprintd[2379]: async:error 
[fpi_drvcb_enroll_stage_completed] BUG at async.c:161
nov. 09 17:27:35 mycomputer fprintd[2379]: async:debug 
[fpi_drvcb_enroll_stage_completed] result -71
nov. 09 17:27:35 mycomputer fprintd[2379]: enroll_stage_cb: result -71
nov. 09 17:27:35 mycomputer fprintd[2379]: elan:debug [dev_deinit]
nov. 09 17:27:35 mycomputer fprintd[2379]: async:debug 
[fpi_drvcb_close_complete]
nov. 09 17:27:35 mycomputer fprintd[2379]: no longer monitoring fd 15
nov. 09 17:27:35 mycomputer fprintd[2379]: released device 0
```