How to make add-on VGA output under linux

How to make add-on VGA output under linux  2017.08.15 update

1.Setup add-on VGA card
2.Boot to OS
3.#Xorg -configure
    It will generate a file Xorg.conf.new under /root
4.#rm /etc/X11/Xorg.conf
5.#cp /root/Xorg.conf.new /etc/X11/Xorg.conf
6.#init 6


----------------------------------------------
For nvidia GPU

You can work around this problem by specifying the bus ID of the device
    you wish to use. For more details, please search the xorg.conf manual page
    for "BusID". You can configure the X server with an X screen on each
    NVIDIA GPU by running:

    
    
    nvidia-xconfig --enable-all-gpus
    
"


The other option is to manually update the xorg.conf file by adding the BusID information in the device section so that it points directly to the Quadro P6000 card if you only want to use this device for display.
 
Below is what the updated device section would look like in the xorg.conf file for the system that is currently being tested.
"
Section "Device"
        Identifier  "Device0"
        Driver      "nvidia"
        VendorName  "NVIDIA Corporation"
        # Edit the BusID with the location of your graphics card
        BusID       "PCI:134:0:0"
    EndSection
"

The BusID ("PCI:134:0:0" in this particular case) can be determined from the lspci command ouput. 

Excerpt from the lspci command output attached earlier to this defect:
"
86:00.0 VGA compatible controller: NVIDIA Corporation GP102GL [Quadro P6000] (rev a1) (prog-if 00 [VGA controller])
"

86 Hex = 134 Decimal, the BusID command requires the address to be in decimal format, but the lspci command display the address in hex format.