[fprint] VFS301 - Doesn't proceed after first enroll

[Vasily Khoruzhick]

Hi Prasanna,

Please keep mailing list in CC, this information could be interesting
to other people.

On Wed, Apr 1, 2015 at 2:03 PM, Prasanna Venkadesh <prasmailme at gmail.com> wrote:
>
> Thanks for letting me know that.
>
> If you people don't mind, I have zero experience with writing device drivers
> but interested to learn and contribute. If anyone of you could point me to a
> source where I can start learning?

Start with downloading libfprint sources from git, see development
section of http://www.freedesktop.org/wiki/Software/fprint/libfprint/

Driver you're interested in is at libfprint/drivers/vfs301.c

A driver has to start another capture after successful (or
unsuccessful) previous one, unless imgdev core didn't explicitly ask
to stop scan by calling dev_deactivate(). But currently vfs301 driver
doesn't support deactivation properly (see dev_deactivate() function,
it doesn't even bother to cancel flying transfers). You need to modify
the driver to respect this requirement and fix dev_deactivate() to do
proper deactivation.

Regards,
Vasily