How to fix laptop brightness when charging

On Windows 11 laptops like HP OmniBook X Flip 14, automatic dimming while plugged in is typically caused by one of these system features:

1. Content-based brightness/contrast (already turned off in this case).
2. Automatic brightness based on ambient lighting.
3. Power-plan–specific brightness levels for “On battery” vs “Plugged in.”
4. Vendor power-saving technologies tied to AC/DC changes.

Based on the provided information, the following system-level checks and workarounds are available:

1. Verify automatic brightness based on lighting conditions
   1. Open Start > Settings > System > Display.
   2. Select Brightness.
   3. Make sure brightness automatically when lighting changes is turned Off. This feature uses the ambient light sensor (if present) and can change brightness when the environment or power state changes.
2. Re-check content-based brightness control
   1. In Settings > System > Display > Brightness, confirm Change brightness based on content is set to Off.
   2. If it is set to Always or On battery only, Windows will adjust brightness and contrast dynamically, which can look like dimming when scenes change or when power state changes.
3. Manually override brightness after power changes On HDR-capable or modern high‑resolution displays, brightness can change when switching between battery and AC power, or after lid/power events. When dimming occurs after plugging in:
   1. Go to Settings > System > Display.
   2. Use the Brightness slider to manually set the desired brightness. This manual adjustment forces the correct brightness level again and is the documented workaround for unexpected brightness changes on some HDR-capable laptops.
4. Check per-power-profile brightness Some power plans maintain different brightness levels for On battery and Plugged in and can unexpectedly sync or override each other after restarts or power changes.
   1. Open Control Panel.
   2. Go to Hardware and Sound > Power Options.
   3. Next to the active plan, select Change plan settings.
   4. Set the Adjust plan brightness sliders for both On battery and Plugged in to the same level.
   5. Select Change advanced power settings, expand Display > Display brightness, and ensure the On battery and Plugged in values match.
5. Use known triggers to “reset” brightness logic On some recent Windows 11 builds, auto-brightness logic can get stuck until a brightness-related event occurs. If brightness keeps dimming or fails to respond correctly after plugging in, doing any of the following can re-activate the correct behavior:
   • Move the Brightness slider once or use the keyboard brightness keys.
   • Plug or unplug the power adapter again.
   • Turn Battery saver on and then off.
   • Put the device to sleep on battery, then wake it.
   Any of these actions can re-sync the brightness logic and restore normal behavior after a power-state change.
6. Vendor-specific (HP) settings The context does not list HP-specific utilities or hidden toggles. If HP software is installed (for example, HP power or display tools), check within those apps for any “adaptive,” “power saving,” or “eye comfort” display options and disable them so that Windows settings fully control brightness.

If the issue persists after matching brightness for both power states, disabling automatic/content-based brightness, and using the reset triggers above, the next step is to look for firmware/driver updates from HP (especially graphics and display-related components), as vendor updates have resolved display issues in similar scenarios.

References:

• Change display brightness and color in Windows
• HDR settings in Windows
• Adaptive brightness
• My laptop no longer adjusts screen brightness - Microsoft Q&A