I'm using this for my Razer Blade 17 Pro 2020 to keep the brightness slider in Ubuntu GNOME up to date with the actual brightness of the display.
It's not pretty but it works. Remember to add this to your startup (gnome-session-properties).
Licensed under MIT. Use however.
| #!/usr/bin/env python3 | |
| import os | |
| import sys | |
| import time | |
| import subprocess | |
| DISPLAY_NAME = "DP-2" # Run `xrandr` to see the active display | |
| PATH_BACKLIGHT = "/sys/class/backlight/acpi_video0/actual_brightness" | |
| MIN_BRIGHTNESS = 0.2 # Don't let people turn off the screen completely | |
| DEFAULT_BRIGHTNESS = 0.5 # In case we cannot read the source file | |
| POLLING_INTERVAL_SECONDS = 0.5 | |
| if not os.path.exists(PATH_BACKLIGHT): | |
| # We're on Intel Graphics. No need to run this monitor | |
| sys.stdout.write("Ignoring self because of non-NVIDIA Graphics\n") | |
| sys.exit() | |
| def getBrightness(): | |
| try: | |
| with open(PATH_BACKLIGHT) as file: | |
| value = file.read().strip() | |
| fraction = int(value) / 100 | |
| except: | |
| sys.stderr.write("ERROR: Failed to read backlight value\n") | |
| fraction = DEFAULT_BRIGHTNESS | |
| return MIN_BRIGHTNESS if fraction < MIN_BRIGHTNESS else fraction | |
| def setBrightness(value): | |
| subprocess.Popen(["xrandr", "--output", DISPLAY_NAME, "--brightness", str(value)], | |
| stdin =subprocess.DEVNULL, | |
| stdout=subprocess.DEVNULL, | |
| stderr=subprocess.DEVNULL, | |
| bufsize=0) | |
| setBrightness(getBrightness()) | |
| while 1: | |
| time.sleep(POLLING_INTERVAL_SECONDS) | |
| setBrightness(getBrightness()) |