[fprint] uru4000, number of enroll stages

[Timo Teras]

On Wed, 25 Jun 2014 09:15:29 +0300
Vasily Khoruzhick <anarsoul at gmail.com> wrote:

> > It did. Thanks. Forget the earlier patch, it's irrelevant and the
> > original code is right. Seems the bug is in the generic code and
> > affects all drivers that are capable of 'finger present' detection.
> > 
> > It seems to be a bug since 2008 but mostly unnoticed due to doing
> > only that one enrollment.
> 
> Well, I'm testing libfprint on several Authentec scanners and on
> single UPEK, and it didn't affect any of my devices.

It depends a lot on the driver internals if the bug affects it or not.
But fundamentally there was a confusion in enum type. The mismatch
basically caused driver to go to 'capture' mode immediately instead of
'await finger on' as intended. If the device does mandatory asynchronous
hardware finger recognition like uru does, there are high changes that
the bug affects it.

-Timo