Created attachment 122966 [details]
the full kernel log

I have a Lenovo P50 notebook with a docking station and two externally attached
monitors, but I won't get more than one external "connected" display (+ the
internal LCD). I tried to connect via DVI, DisplayPort and HDMI in all
combinations, but xrandr only shows
eDP-1 connected
DP-1 connected
DP-2 disconnected
DP-3 disconnected

Sometimes I manage to get both external monitors to display the same contents,
but I have never managed to use one as primary and the other as secondary
display.

01:00.0 VGA compatible controller: NVIDIA Corporation GM107GLM [Quadro M2000M]
(rev a2) (prog-if 00 [VGA controller])
01:00.1 Audio device: NVIDIA Corporation Device 0fbc (rev a1)

Linux nb 4.4.0-1-amd64 #1 SMP Debian 4.4.6-1 (2016-03-17) x86_64 GNU/Linux
xserver-xorg                   1:7.7+14
xserver-xorg-core              2:1.18.3-1
xserver-xorg-video-nouveau     1:1.0.12-1+b1
libdrm2:amd64                  2.4.67-1
libdrm-nouveau2:amd64          2.4.67-1

libegl1-mesa:amd64           11.1.2-1
libgl1-mesa-dri:amd64        11.1.2-1
libgl1-mesa-glx:amd64        11.1.2-1
libglapi-mesa:amd64          11.1.2-1
libgles1-mesa:amd64          11.1.2-1
libgles2-mesa:amd64          11.1.2-1
libglu1-mesa:amd64           9.0.0-2.1
libwayland-egl1-mesa:amd64   11.1.2-1
mesa-utils                   8.3.0-1
mesa-vdpau-drivers:amd64     11.1.2-1

Bios is the most recent one from 2016-04-1 (1.21).