title: How can I modify xorg.conf file to force X server to run on a specific GPU? (I am using multiple GPUs)
body: <p>I'm running 2 GPUs and I'm trying to force X server to run on one GPU.
  According to this website : <a href="http://nvidia.custhelp.com/app/answers/detail/a_id/3029/~/using-cuda-and-x" rel="noreferrer">http://nvidia.custhelp.com/app/answers/detail/a_id/3029/~/using-cuda-and-x</a> , here is how i should proceed : </p>
  
  <blockquote>
    <p>The X display should be forced onto a single GPU using the BusID
    parameter in the relevant "Display" section of the xorg.conf file. In
    addition, any other "Display" sections should be deleted. For example:
    BusID "PCI:34:0:0"</p>
  </blockquote>
  
  <p>Here is my xorg.conf file :</p>
  
  <pre><code># nvidia-xconfig: X configuration file generated by nvidia-xconfig
  # nvidia-xconfig:  version 304.64  (buildmeister@swio-display-x86-rhel47-12)  Tue Oct 30 12:04:46 PDT 2012
  
  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 "Screen"
      Identifier     "Screen0"
      Device         "Device0"
      Monitor        "Monitor0"
      DefaultDepth    24
      SubSection     "Display"
          Depth       24
      EndSubSection
  EndSection
  </code></pre>
  
  <p>So I tried to modify the subsection display with the correct BusID but it still does not work, I also tried to put it in the section Device.</p>
  
  <p>Anyone knows how i could do that ?</p>