xorg.conf

Section "ServerLayout"
    Identifier     "X.org Configured"
        Screen       0 "Screen0" 0 0
        InputDevice    "Mouse0" "CorePointer"
    InputDevice    "Keyboard0" "CoreKeyboard"
EndSection

Section "Files"
    ModulePath   "/usr/lib/xorg/modules"
    FontPath     "/usr/share/fonts/misc"
    FontPath     "/usr/share/fonts/TTF"
    FontPath     "/usr/share/fonts/OTF"
    FontPath     "/usr/share/fonts/Type1"
    FontPath     "/usr/share/fonts/100dpi"
    FontPath     "/usr/share/fonts/75dpi"
EndSection

Section "Module"
    Load  "glx"
EndSection

Section "InputDevice"
    Identifier  "Keyboard0"
    Driver      "kbd"
EndSection

Section "InputDevice"
    Identifier  "Mouse0"
    Driver      "mouse"
    Option      "Protocol" "auto"
    Option      "Device" "/dev/input/mice"
    Option      "ZAxisMapping" "4 5 6 7"
EndSection

Section "Monitor"
    Identifier   "Monitor-HDMI-A-1"
    VendorName   "Monitor Vendor"
    ModelName    "Monitor Model"
#        Option "Enable" "True"
EndSection

Section "Monitor"
    Identifier   "Monitor1"
    VendorName   "Monitor Vendor"
    ModelName    "Monitor Model"
#        Option "Enable" "True"
EndSection


Section "Device"
        ### Available Driver options are:-
        ### Values: <i>: integer, <f>: float, <bool>: "True"/"False",
        ### <string>: "String", <freq>: "<f> Hz/kHz/MHz",
        ### <percent>: "<f>%"
        ###[arg]: primary
        Option     "Accel"              "True"  # [<bool>]
        #Option     "SWcursor"              # [<bool>]
        #Option     "EnablePageFlip"        # [<bool>]
        #Option     "SubPixelOrder"         # [<str>]
        #Option     "ZaphodHeads"           # <str>
        #Option     "AccelMethod"           # <str>
        Option     "DRI3"               "True"  # [<bool>]
        #Option     "DRI"                   # <i>
        #Option     "ShadowPrimary"         # [<bool>]
        Option     "TearFree"           "True"  # [<bool>]
        #Option     "DeleteUnusedDP12Displays"  # [<bool>]
        #Option     "VariableRefresh"       # [<bool>]
    Identifier  "Card0"
    Driver      "amdgpu"
    BusID       "PCI:6:0:0"
EndSection

Section "Device"
        ### Available Driver options are:-
        ### Values: <i>: integer, <f>: float, <bool>: "True"/"False",
        ### <string>: "String", <freq>: "<f> Hz/kHz/MHz",
        ### <percent>: "<f>%"
        ### [arg]: arg optional
        #Option     "SWcursor"              # [<bool>]
        #Option     "HWcursor"              # [<bool>]
        #Option     "NoAccel"               # [<bool>]
        #Option     "ShadowFB"              # [<bool>]
        #Option     "VideoKey"              # <i>
        #Option     "WrappedFB"             # [<bool>]
        #Option     "GLXVBlank"             # [<bool>]
        #Option     "ZaphodHeads"           # <str>
        #Option     "PageFlip"              # [<bool>]
        #Option     "SwapLimit"             # <i>
        #Option     "AsyncUTSDFS"           # [<bool>]
        #Option     "AccelMethod"           # <str>
        #Option     "DRI"                   # <i>
    Identifier  "Card1"
    Driver      "nouveau"
    BusID       "PCI:5:0:0"
EndSection

Section "Screen"
    Identifier "Screen0"
    Device  "Card0"
        Monitor    "Monitor-HDMI-A-1"
    SubSection "Display"
        Viewport   0 0
        Depth     24
    EndSubSection
EndSection

Section "Screen"
    Identifier "Screen0"
    Device  "Card1"
        Monitor    "Monitor1"
    SubSection "Display"
        Viewport   1920 0
        Depth     24
    EndSubSection
EndSection