From ArchWiki

Section "ServerLayout"
  Identifier     "Simple Layout"
  Screen      0  "aticonfig-Screen[0]" 0 0
  InputDevice    "Mouse1" "CorePointer"
  InputDevice    "Keyboard1" "CoreKeyboard"
EndSection

Section "Files"
  FontPath     "/usr/share/fonts/misc"
  FontPath     "/usr/share/fonts/75dpi"
  FontPath     "/usr/share/fonts/100dpi"
  FontPath     "/usr/share/fonts/Type1"
EndSection

Section "Module"
  Load "freetype"
  Load "xtt"
  Load  "dbe"  	# Double buffer extension
  SubSection "extmod"
  	Option	    "omit xfree86-dga"   # don't initialise the DGA extension
  EndSubSection
EndSection

Section "InputDevice"
  Identifier  "Keyboard1"
  Driver      "kbd"
  Option	    "AutoRepeat" "500 30"
  Option	    "XkbRules" "xorg"
  Option	    "XkbModel" "pc105"
  Option	    "XkbLayout" "latam"
  Option            "XkbOptions"    "lv3:rwin_switch"
EndSection

Section "InputDevice"
  Identifier  "Mouse1"
  Driver      "mouse"
  Option	    "Protocol" "Auto"	# Auto detect
  Option	    "Device" "/dev/input/mice"
  Option	    "ZAxisMapping" "4 5 6 7"
  Option            "MinSpeed"              "1.0"
  Option            "MaxSpeed"              "1.0"
EndSection

Section "Monitor"
  Identifier   "aticonfig-Monitor[0]"
  Option	    "VendorName" "ATI Proprietary Driver"
  Option	    "ModelName" "Generic Autodetecting Monitor"
  Option	    "DPMS" "true"
EndSection

Section "Device"
  Identifier  "aticonfig-Device[0]"
  Driver      "fglrx"
EndSection

Section "Screen"
  Identifier "aticonfig-Screen[0]"
  Device     "aticonfig-Device[0]"
  Monitor    "aticonfig-Monitor[0]"
  DefaultDepth     24
  SubSection "Display"
  	Viewport   0 0
  	Depth     24
  EndSubSection
EndSection

Section "DRI"
  Mode 0666
EndSection