A script for adjusting screen brightness in Dell laptops with OLED screens in Ubuntu. It requires xrandr to be installed.

screen-brightness

#!/usr/bin/python3

import logging
import os
import subprocess
import sys
from typing import Literal

logging.basicConfig(level=logging.DEBUG)

FILE_PATH = os.path.join(
    os.path.dirname(os.path.realpath(__file__)), ".screen-brightness"
)


def read_current_level() -> float:
    if not os.path.isfile(FILE_PATH):
        return 1
    with open(
        file=FILE_PATH,
        mode="r",
        encoding="utf-8",
    ) as file:
        current_level = file.readline().strip()
        return float(current_level)


def save_level(level: float) -> None:
    with open(
        file=FILE_PATH,
        mode="w",
        encoding="utf-8",
    ) as file:
        file.write(str(level))


def adjust_level(method: Literal["up", "down"]) -> None:
    adjuster = 0.05 if method == "up" else -0.05
    current_level = read_current_level()
    adjusted_level = current_level + adjuster
    if adjusted_level > 1:
        adjusted_level = 1
    if adjusted_level < 0.2:
        adjusted_level = 0.2
    logging.debug(f"Setting screen brightness to {adjusted_level}.")
    subprocess.run(["xrandr", "--output", "eDP-1", "--brightness", str(adjusted_level)])
    save_level(level=adjusted_level)


if __name__ == "__main__":
    METHOD = sys.argv[1] if len(sys.argv) > 1 else "up"
    adjust_level(method=METHOD)

I use this script on Ubuntu 20.04. My laptop screen name was eDP-1 in xrandr.

Usage:

# increase brightness
./screen-brightness up

# lower brightness
./screen-brightness down

You can add custom keyboard shortcuts to invoke the script:

Very good script, from the terminal works fine, nonetheless when I call the script from the Keyboard Shortcut nothing happens, any idea what I might be doing wrong, I have tried different keyboard shortcuts combinations, thank you

it is working now, it was a permissions problem and I was using Wayland, I had to switch to X11, Wayland doesn't support the xrandr command, all good now, thank you

it is working now, it was a permissions problem and I was using Wayland, I had to switch to X11, Wayland doesn't support the xrandr command, all good now, thank you

Thanks for posting the solution to your problem 👍

In one of the latest 5.11 updates fixed this issue, because now I can adjust the OLED brightness with the system keyboard keys

I have a Lenovo X1 Yoga 1st Gen with OLED Screen, Ubuntu 21.10 with Kernel 5.13 installed and changing the screen brightness still doesn't work. Could anybody please help me? I have no idea what to do.

This is awesome. Very simple, much wow. Thanks for the work, man!

FYI, I tried to use the brightness keys on my laptop to be the shortcut to the script (Galaxy Book2 360 with Pop!_OS) and it didn't work. Apparently the brightness keys do something, so they don't call the script. Ended up using CTRL+SHIFT+F2|F3 which match where the brightness keys are.

Is there a reason it stops at 0.2? Is it not safe or something? Since my display is OLED, depending on the lighting values below 0.2 are acceptable, but now I'm wondering if I might screwing up my display or something.

I made a small change to support basically turning off the display and have smaller intervals below 0.2. Here's the patch if anyone is interested:

diff --git a/screen-brightness b/screen-brightness
index 84c8eef..7d4bd11 100755
--- a/screen-brightness
+++ b/screen-brightness
@@ -35,13 +35,13 @@ def save_level(level: float) -> None:
 
 
 def adjust_level(method: Literal["up", "down"]) -> None:
-    adjuster = 0.05 if method == "up" else -0.05
     current_level = read_current_level()
-    adjusted_level = current_level + adjuster
+    adjuster = 0.02 if current_level <= 0.2 else 0.05
+    adjusted_level = current_level + adjuster if method == "up" else current_level - adjuster
     if adjusted_level > 1:
         adjusted_level = 1
-    if adjusted_level < 0.2:
-        adjusted_level = 0.2
+    if adjusted_level < 0.0:
+        adjusted_level = 0.0
     logging.debug(f"Setting screen brightness to {adjusted_level}.")
     subprocess.run(["xrandr", "--output", "eDP-1", "--brightness", str(adjusted_level)])
     save_level(level=adjusted_level)

Is there a reason it stops at 0.2? Is it not safe or something? Since my display is OLED, depending on the lighting values below 0.2 are acceptable, but now I'm wondering if I might screwing up my display or something.

No particular reason, it was a limit I added which suited my needs. It shouldn't break anything allowing it to go to 0.0.