[fprint] Would you please help to create the function to update the template for "verify" and "identify"?

[Bastien Nocera]

Hello Dave,

Sorry about the late reply.

On Wed, 2019-01-02 at 10:58 +0800, Dave.Wang wrote:
> Dear,
>  
> We want to implement the primitive driver which will use our "match
> on chip" sensor.
> Our "match on chip" sensor has function which can update the template
> after obtaining matched result for "verify" or "identify". It will
> make better performance.

Is there persistent storage on the device, or would you need to "load"
some data from the disk?

> As I know, the template located in "/var/lib/fprint/.. " is only
> stored by "fprintd-enroll" now.
> Would you please help to create the function to update the template
> for "verify" and "identify"?

The driver does not know how to load or save data to disk.

The enrolling process will give out a "struct fp_print_data" variable
that the front-end (usually fprintd) can save to disk, and which the
front-end will load from disk to pass to the driver for each
"fp_async_verify_start" call.

There currently isn't any way for the driver to modify that data that
was saved once during enrollment, but I would imagine that it could be
possible to pass that data back to fprintd via the
fp_async_verify_stop() result.

Is there any way you could try implementing your driver without that
feature first, and then we can figure out how to implement the template
update on disk.

Cheers