[Fingerforce-devel] libpam-thinkfinger/libpam-fprint and screensavers

[Luca Capello]

Hello,

on Philipp Kern's request, I've investigated a bit more how ThinkFinger
and fprint work with some common screensavers, specifically xlockmore
and xscreensaver/gnome-screensaver [1].  This is also useful to smooth
the ThinkFinger -> fprint transition.

The main document about the situation is on ThinkWiki [2].

1) permissions for the USB device

   Both ThinkFinger and fprint needs special permissions for the USB
   device, otherwise they cannot access it.  I filed bug #469043 [3]
   only for ThinkFinger, since questionable is which group should own
   the USB device, a 'fingerprint' one or a "more general" one like
   'plugdev'.  As soon as a solution has been found, the same should be
   included in fprint as well.  Moreover, since this is critical to use
   the device (and the library) with any program, I'm for adding the
   udev rule (and the group creation) into the main library package.

2) permissions for the uinput device

   This seems to be ThinkFinger-specific (bug #469048 [4]), thus I
   planned to add it to the libpam-thinkfinger package.

3) gnome-screensaver

   It needs only the permissions above :-)

4) xscreensaver

   After having set the permissions above it works nicely with
   ThinkFinger, but not with fprint: first you need to press ENTER or
   the OK button, then you can swipe your finger (bug #469059 [5]).

5) xlockmore

   no fingerprint prompt is shown in both case, but while with fprint
   the situation is the same as xscreensaver (you need to press ENTER
   before start swiping your finger), with ThinkFinger xlockmore hangs
   when you enter your password (bug #469034 [6], maybe related to bug
   #463261 [7]).

Thx, bye,
Gismo / Luca

Footnotes: 
[1] I'm mostly a GTK+ guy and don't have any Qt software installed...
[2] http://www.thinkwiki.org/wiki/How_to_enable_the_fingerprint_reader_with_ThinkFinger#xscreensaver.2Fgnome-screensaver
[3] http://bugs.debian.org/469043
[4] http://bugs.debian.org/469048
[5] http://bugs.debian.org/469059
[6] http://bugs.debian.org/469034
[7] http://bugs.debian.org/463261