intj@intjDesktop:/usr/share/X11/xorg.conf.d$ cd /sys/class/backlight/
intj@intjDesktop:/sys/class/backlight$ ls

intj@intjDesktop:/sys/class/backlight$ xrandr -q | grep " connected"
DVI-D-0 connected 1920x1080+2560+360 (normal left inverted right x axis y axis) 477mm x 268mm
DP-1 connected primary 2560x1440+0+0 (normal left inverted right x axis y axis) 598mm x 336mm

intj@intjDesktop:/sys/class/backlight$ sudo find /sys/ -type f -iname '*brightness*'
/sys/devices/pci0000:00/0000:00:14.0/usb3/3-9/3-9:1.0/0003:413C:2003.0007/input/input7/input7::numlock/max_brightness
/sys/devices/pci0000:00/0000:00:14.0/usb3/3-9/3-9:1.0/0003:413C:2003.0007/input/input7/input7::numlock/brightness
/sys/devices/pci0000:00/0000:00:14.0/usb3/3-9/3-9:1.0/0003:413C:2003.0007/input/input7/input7::capslock/max_brightness
/sys/devices/pci0000:00/0000:00:14.0/usb3/3-9/3-9:1.0/0003:413C:2003.0007/input/input7/input7::capslock/brightness
/sys/devices/pci0000:00/0000:00:14.0/usb3/3-9/3-9:1.0/0003:413C:2003.0007/input/input7/input7::scrolllock/max_brightness
/sys/devices/pci0000:00/0000:00:14.0/usb3/3-9/3-9:1.0/0003:413C:2003.0007/input/input7/input7::scrolllock/brightness
/sys/devices/pci0000:00/0000:00:14.0/usb3/3-1/3-1:1.0/0003:045E:07A5.0001/input/input2/input2::capslock/max_brightness
/sys/devices/pci0000:00/0000:00:14.0/usb3/3-1/3-1:1.0/0003:045E:07A5.0001/input/input2/input2::capslock/brightness
/sys/devices/pci0000:00/0000:00:14.0/usb3/3-1/3-1:1.0/0003:045E:07A5.0001/input/input2/input2::numlock/max_brightness
/sys/devices/pci0000:00/0000:00:14.0/usb3/3-1/3-1:1.0/0003:045E:07A5.0001/input/input2/input2::numlock/brightness
/sys/devices/pci0000:00/0000:00:14.0/usb3/3-1/3-1:1.0/0003:045E:07A5.0001/input/input2/input2::scrolllock/max_brightness
/sys/devices/pci0000:00/0000:00:14.0/usb3/3-1/3-1:1.0/0003:045E:07A5.0001/input/input2/input2::scrolllock/brightness
/sys/devices/virtual/input/input21/input21::mail/max_brightness
/sys/devices/virtual/input/input21/input21::mail/brightness
/sys/devices/virtual/input/input21/input21::sleep/max_brightness
/sys/devices/virtual/input/input21/input21::sleep/brightness
/sys/devices/virtual/input/input21/input21::charging/max_brightness
/sys/devices/virtual/input/input21/input21::charging/brightness
/sys/devices/virtual/input/input21/input21::numlock/max_brightness
/sys/devices/virtual/input/input21/input21::numlock/brightness
/sys/devices/virtual/input/input21/input21::suspend/max_brightness
/sys/devices/virtual/input/input21/input21::suspend/brightness
/sys/devices/virtual/input/input21/input21::kana/max_brightness
/sys/devices/virtual/input/input21/input21::kana/brightness
/sys/devices/virtual/input/input21/input21::capslock/max_brightness
/sys/devices/virtual/input/input21/input21::capslock/brightness
/sys/devices/virtual/input/input21/input21::scrolllock/max_brightness
/sys/devices/virtual/input/input21/input21::scrolllock/brightness
/sys/devices/virtual/input/input21/input21::misc/max_brightness
/sys/devices/virtual/input/input21/input21::misc/brightness
/sys/devices/virtual/input/input21/input21::mute/max_brightness
/sys/devices/virtual/input/input21/input21::mute/brightness
/sys/devices/virtual/input/input21/input21::compose/max_brightness
/sys/devices/virtual/input/input21/input21::compose/brightness
/sys/module/video/parameters/brightness_switch_enabled
intj@intjDesktop:/sys/class/backlight$