Eu tenho quase o mesmo problema descrito aqui black tela no segundo monitor
Qualquer monitor é configurado como monitor 0 e a tela 0 funciona. o outro fica preto, mas tem o cursor de "cruz" se eu colocar o mouse sobre ele. Não consigo arrastar ou criar uma janela no segundo. As configurações da Nvidia reconhecem o segundo monitor bem, mas as configurações de exibição do Ubuntu não. Aqui está o meu xorg.conf:
# nvidia-settings: X configuration file generated by nvidia-settings
# nvidia-settings: version 361.42 (buildd@lgw01-18) Tue Apr 5 14:33:28 UTC 2016
# nvidia-xconfig: X configuration file generated by nvidia-xconfig
# nvidia-xconfig: version 370.28 (buildmeister@swio-display-x64-rhel04-17) Thu Sep 1 20:22:52 PDT 2016
Section "ServerLayout"
Identifier "Layout0"
Screen 0 "Screen0" 0 0
Screen 1 "Screen1" RightOf "Screen0"
InputDevice "Keyboard0" "CoreKeyboard"
InputDevice "Mouse0" "CorePointer"
Option "Xinerama" "0"
EndSection
Section "Files"
EndSection
Section "InputDevice"
# generated from default
Identifier "Mouse0"
Driver "mouse"
Option "Protocol" "auto"
Option "Device" "/dev/psaux"
Option "Emulate3Buttons" "no"
Option "ZAxisMapping" "4 5"
EndSection
Section "InputDevice"
# generated from default
Identifier "Keyboard0"
Driver "kbd"
EndSection
Section "Monitor"
Identifier "Monitor0"
VendorName "Unknown"
ModelName "DELL U2415"
HorizSync 30.0 - 83.0
VertRefresh 49.0 - 61.0
Option "DPMS"
EndSection
Section "Monitor"
Identifier "Monitor1"
VendorName "Unknown"
ModelName "SAMSUNG"
HorizSync 15.0 - 81.0
VertRefresh 24.0 - 75.0
Option "DPMS"
EndSection
Section "Device"
Identifier "Device0"
Driver "nvidia"
VendorName "NVIDIA Corporation"
BoardName "Quadro K420"
BusID "PCI:5:0:0"
EndSection
Section "Device"
Identifier "Device1"
Driver "nvidia"
VendorName "NVIDIA Corporation"
BoardName "Quadro K420"
BusID "PCI:1:0:0"
EndSection
Section "Screen"
Identifier "Screen0"
Device "Device0"
Monitor "Monitor0"
DefaultDepth 24
Option "Stereo" "0"
Option "nvidiaXineramaInfoOrder" "DFP-2.8"
Option "metamodes" "nvidia-auto-select +0+0"
Option "SLI" "Off"
Option "MultiGPU" "on"
Option "BaseMosaic" "off"
SubSection "Display"
Depth 24
EndSubSection
EndSection
Section "Screen"
Identifier "Screen1"
Device "Device1"
Monitor "Monitor1"
DefaultDepth 24
Option "Stereo" "0"
Option "metamodes" "nvidia-auto-select +0+0"
Option "SLI" "Off"
Option "MultiGPU" "on"
Option "BaseMosaic" "off"
SubSection "Display"
Depth 24
EndSubSection
EndSection
Aqui está a saída do xrandr:
xrandr
Screen 0: minimum 8 x 8, current 1920 x 1200, maximum 16384 x 16384
DVI-I-0 disconnected (normal left inverted right x axis y axis)
DP-1.8 connected primary 1920x1200+0+0 (normal left inverted right x axis y axis) 518mm x 324mm
1920x1200 59.95*+ 59.88
1920x1080 60.00 59.94 50.00 29.97 25.00 23.97 60.05 60.00 50.04
1600x1200 60.00
1280x1024 75.02 60.02
1280x720 60.00 59.94 50.00
1152x864 75.00
1024x768 75.03 60.00
800x600 75.00 60.32
720x576 50.00 50.08
720x480 59.94 60.05
640x480 75.00 59.94 59.93
DVI-I-1 disconnected (normal left inverted right x axis y axis)
DP-0 disconnected (normal left inverted right x axis y axis)
DP-1 disconnected (normal left inverted right x axis y axis)