Ubuntu 18.04 + Cuda 390 НЕ обнаруживает второй монитор на DisplayPort

Моя машина имеет NVIDIA QUADRо видеокарта K2200 с GPU.

Я установил Ubuntu 18.04 и nvidia-390.48, а также CUDA 9.0 (я использую Cuda 9.0, потому что старшие версии не работают с крисом и потоком тензора).

Во всяком случае, cuda, крис и tensorflow все хорошо работают. Однако Ubuntu не обнаруживает второй монитор, который подключен через DisplayPort, в то время как первый соединен через порт DVI.

Вот вывод nvidia-smi:

+-----------------------------------------------------------------------------+
| NVIDIA-SMI 390.48                 Driver Version: 390.48                    |
|-------------------------------+----------------------+----------------------+
| GPU  Name        Persistence-M| Bus-Id        Disp.A | Volatile Uncorr. ECC |
| Fan  Temp  Perf  Pwr:Usage/Cap|         Memory-Usage | GPU-Util  Compute M. |
|===============================+======================+======================|
|   0  Quadro K2200        Off  | 00000000:03:00.0  On |                  N/A |
| 42%   33C    P8     1W /  39W |    185MiB /  4035MiB |      0%      Default |
+-------------------------------+----------------------+----------------------+

+-----------------------------------------------------------------------------+
| Processes:                                                       GPU Memory |
|  GPU       PID   Type   Process name                             Usage      |
|=============================================================================|
|    0       924      G   /usr/lib/xorg/Xorg                            99MiB |
|    0      1390      G   /usr/bin/gnome-shell                          73MiB |
|    0      1918      G   /usr/lib/firefox/firefox                       1MiB |
|    0      1991      G   /usr/lib/firefox/firefox                       1MiB |
|    0      2148      G   /usr/lib/firefox/firefox                       1MiB |
+-----------------------------------------------------------------------------+

и вот вывод xrandr:

Screen 0: minimum 8 x 8, current 1920 x 1080, maximum 16384 x 16384
DVI-I-0 disconnected (normal left inverted right x axis y axis)
DVI-I-1 connected primary 1920x1080+0+0 (normal left inverted right x axis y axis) 531mm x 298mm
   1920x1080     60.00*+
   1280x1024     75.02    60.02  
   1152x864      75.00  
   1024x768      75.03    60.00  
   800x600       75.00    60.32  
   640x480       75.00    59.94  
DP-0 disconnected (normal left inverted right x axis y axis)
DP-1 disconnected (normal left inverted right x axis y axis)
DP-2 disconnected (normal left inverted right x axis y axis)
DP-3 disconnected (normal left inverted right x axis y axis)

и вот содержание моего xorg.conf файла:

# nvidia-xconfig: X configuration file generated by nvidia-xconfig
# nvidia-xconfig:  version 390.48  (buildmeister@swio-display-x86-rhel47-07)  Thu Mar 22 01:07:32 PDT 2018

Section "ServerLayout"
    Identifier     "Layout0"
    Screen      0  "Screen0"
    InputDevice    "Keyboard0" "CoreKeyboard"
    InputDevice    "Mouse0" "CorePointer"
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      "Unknown"
    HorizSync       28.0 - 33.0
    VertRefresh     43.0 - 72.0
    Option         "DPMS"
EndSection

Section "Device"
    Identifier     "Device0"
    Driver         "nvidia"
    VendorName     "NVIDIA Corporation"
EndSection

Section "Files"
    ModulePath      "/usr/local/cuda/lib64/"
    ModulePath      "/usr/lib/xorg/modules"
EndSection

Section "Screen"
    Identifier     "Screen0"
    Device         "Device0"
    Monitor        "Monitor0"
    DefaultDepth    24
    SubSection     "Display"
        Depth       24
    EndSubSection
EndSection