nvidia-settings обнаруживает отсутствие отображения

У меня есть Ubuntu 14.04 и драйвер nvidia 331.38. В моем ноутбуке GeForce GT 555M и графическая карта Intel. Ubuntu работает отлично, за исключением одной проблемы. Я хотел подключить два внешних монитора и понял, что nvidia-settings даже не обнаруживает внутренний дисплей ноутбука. В случае, если я подключаю HDMI и VGA, в настройках nvidia отображается только VGA дисплей.

Выход nvidia-xconfig, если не подключены внешние дисплеи:

nvidia-xconfig --query-gpu-info
Number of GPUs: 1

GPU #0:
  Name      : GeForce GT 555M
  UUID      : GPU-6bb6fcda-c642-b2ee-4040-3c4024d7f7a7
  PCI BusID : PCI:1:0:0

  Number of Display Devices: 0

Выход nvidia-xconfig, если подключены два внешних дисплея:

nvidia-xconfig --query-gpu-info
Number of GPUs: 1

GPU #0:
  Name      : GeForce GT 555M
  UUID      : GPU-6bb6fcda-c642-b2ee-4040-3c4024d7f7a7
  PCI BusID : PCI:1:0:0

  Number of Display Devices: 1

  Display Device 0 (DFP-0):
      EDID Name             : Samsung SyncMaster
      Minimum HorizSync     : 30.000 kHz
      Maximum HorizSync     : 81.000 kHz
      Minimum VertRefresh   : 56 Hz
      Maximum VertRefresh   : 75 Hz
      Maximum PixelClock    : 140.000 MHz
      Maximum Width         : 1280 pixels
      Maximum Height        : 1024 pixels
      Preferred Width       : 1280 pixels
      Preferred Height      : 1024 pixels
      Preferred VertRefresh : 60 Hz
      Physical Width        : 380 mm
      Physical Height       : 300 mm

Выход из xrandr:

 Screen 0: minimum 8 x 8, current 1280 x 1024, maximum 16384 x 16384
HDMI-0 connected primary 1280x1024+0+0 (normal left inverted right x axis y axis) 380mm x 300mm
   1280x1024      60.0 +   75.0* 
   1280x960       60.0  
   1152x864       75.0  
   1024x768       75.0     70.1     60.0  
   800x600        75.0     72.2     60.3     56.2  
   640x480        75.0     72.8     59.9  
LVDS-1-0 connected 1280x1024+0+0 344mm x 194mm
   1920x1080      60.0 +   59.9  
   1680x1050      60.0     59.9  
   1600x1024      60.2  
   1400x1050      60.0  
   1280x1024      60.0* 
   1440x900       59.9  
   1280x960       60.0  
   1360x768       59.8     60.0  
   1152x864       60.0  
   1024x768       60.0     60.0  
   960x720        60.0  
   928x696        60.1  
   896x672        60.0  
   960x600        60.0  
   960x540        60.0  
   800x600        60.0     60.3     56.2  
   840x525        60.0     59.9  
   800x512        60.2  
   700x525        60.0  
   640x512        60.0  
   720x450        59.9  
   640x480        60.0     59.9  
   680x384        59.8     60.0  
   576x432        60.1  
   512x384        60.0  
   400x300        60.3     56.3  
   320x240        60.1  
VGA-1-0 connected 1280x1024+0+0 376mm x 301mm
   1280x1024      60.0 +   75.0* 
   1280x960       60.0  
   1152x864       75.0  
   1024x768       75.1     70.1     60.0  
   832x624        74.6  
   800x600        72.2     75.0     60.3     56.2  
   640x480        75.0     72.8     66.7     60.0  
   720x400        70.1  
  1280x1024 (0x4a)  108.0MHz
        h: width  1280 start 1328 end 1440 total 1688 skew    0 clock   64.0KHz
        v: height 1024 start 1025 end 1028 total 1066           clock   60.0Hz
  1280x960 (0x4c)  108.0MHz
        h: width  1280 start 1376 end 1488 total 1800 skew    0 clock   60.0KHz
        v: height  960 start  961 end  964 total 1000           clock   60.0Hz
  1024x768 (0x51)   65.0MHz
        h: width  1024 start 1048 end 1184 total 1344 skew    0 clock   48.4KHz
        v: height  768 start  771 end  777 total  806           clock   60.0Hz
  800x600 (0x58)   40.0MHz
        h: width   800 start  840 end  968 total 1056 skew    0 clock   37.9KHz
        v: height  600 start  601 end  605 total  628           clock   60.3Hz
  800x600 (0x59)   36.0MHz
        h: width   800 start  824 end  896 total 1024 skew    0 clock   35.2KHz
        v: height  600 start  601 end  603 total  625           clock   56.2Hz
  640x480 (0x61)   25.2MHz
        h: width   640 start  656 end  752 total  800 skew    0 clock   31.5KHz
        v: height  480 start  490 end  492 total  525           clock   59.9Hz
  1280x1024 (0x2e9)  135.0MHz
        h: width  1280 start 1296 end 1440 total 1688 skew    0 clock   80.0KHz
        v: height 1024 start 1025 end 1028 total 1066           clock   75.0Hz
  1152x864 (0x2ea)  108.0MHz
        h: width  1152 start 1216 end 1344 total 1600 skew    0 clock   67.5KHz
        v: height  864 start  865 end  868 total  900           clock   75.0Hz
  1024x768 (0x2ec)   75.0MHz
        h: width  1024 start 1048 end 1184 total 1328 skew    0 clock   56.5KHz
        v: height  768 start  771 end  777 total  806           clock   70.1Hz
  800x600 (0x2ee)   50.0MHz
        h: width   800 start  856 end  976 total 1040 skew    0 clock   48.1KHz
        v: height  600 start  637 end  643 total  666           clock   72.2Hz
  800x600 (0x2ed)   49.5MHz
        h: width   800 start  816 end  896 total 1056 skew    0 clock   46.9KHz
        v: height  600 start  601 end  604 total  625           clock   75.0Hz
  640x480 (0x2ef)   31.5MHz
        h: width   640 start  656 end  720 total  840 skew    0 clock   37.5KHz
        v: height  480 start  481 end  484 total  500           clock   75.0Hz

Конфигурация xorg.conf

# nvidia-settings: X configuration file generated by nvidia-settings
# nvidia-settings:  version 331.20  (buildd@roseapple)  Mon Feb  3 15:07:22 UTC 2014

# nvidia-xconfig: X configuration file generated by nvidia-xconfig
# nvidia-xconfig:  version 331.38  (buildmeister@swio-display-x64-rhel04-15)  Wed Jan  8 19:53:14 PST 2014

Section "ServerLayout"
    Identifier     "Layout0"
    Screen      0  "Screen0" 0 0
    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      "Samsung SyncMaster"
    HorizSync       30.0 - 81.0
    VertRefresh     56.0 - 75.0
    Option         "DPMS"
EndSection

Section "Device"
    Identifier     "Device0"
    Driver         "nvidia"
    VendorName     "NVIDIA Corporation"
    BoardName      "GeForce GT 555M"
EndSection

Section "Screen"
    Identifier     "Screen0"
    Device         "Device0"
    Monitor        "Monitor0"
    DefaultDepth    24
    Option         "Stereo" "0"
    Option         "nvidiaXineramaInfoOrder" "DFP-0"
    Option         "metamodes" "1280x1024_75 +0+0"
    Option         "SLI" "Off"
    Option         "MultiGPU" "Off"
    Option         "BaseMosaic" "off"
    SubSection     "Display"
        Depth       24
    EndSubSection
EndSection

Большое спасибо за помощь!