--- Please enter the report below this line. ---
Setting screen brightness with keys shows multiple levels of screen
brightness (progress bar indicates 10 levels),
while only 2 brightnesses levels are recognizable.

Manually setting brightness level with
pkexec xfpm-power-backlight-helper --set-brightness [level]
allows precise control over brightness level (multiple values work here)

Manually setting brightness level with xbacklight works as well.

Debian Release: jessie/sid
500 testing-updates ftp.icm.edu.pl
500 testing-updates ftp.debian.org
500 testing-proposed-updates ftp.icm.edu.pl
500 testing-proposed-updates ftp.debian.org
500 testing security.debian.org
500 testing ftp.icm.edu.pl
500 testing ftp.debian.org
500 stable dl.google.com
--- Package information. ---
Depends (Version) | Installed
============================================-+-================
libc6 (>= 2.4) |
libdbus-1-3 (>= 1.0.2) |
libdbus-glib-1-2 (>= 0.88) |
libgdk-pixbuf2.0-0 (>= 2.22.0) |
libglib2.0-0 (>= 2.37.3) |
libgtk2.0-0 (>= 2.24.0) |
libnotify4 (>= 0.7.0) |
libx11-6 |
libxext6 |
libxfce4ui-1-0 (>= 4.9.0) |
libxfce4util6 (>= 4.9.0) |
libxfconf-0-2 (>= 4.6.0) |
libxrandr2 (>= 2:1.2.99.2) |
upower |
xfce4-power-manager-data (= 1.2.0-4) |


Recommends (Version) | Installed
=============================-+-===========
libpam-systemd | 204-14
systemd-shim |
OR systemd-sysv | 204-14


Suggests (Version) | Installed
==========================================-+-===========
xfce4-power-manager-plugins | 1.2.0-4
udisks | 1.0.5-1