9

Windows only displays its built-in monitor brightness controls on laptops. Historically this has been because desktop monitors tend to have physical brightness controls already (though some don't, thank you Apple) and based on my own personal experience some monitors have unreliable DDC/CI implementations.

enter image description here

But that was in the past. Presently the DDC/CI interface on all of my current monitors seems solid - so I want to get Windows to allow me to control monitor brightness using Windows' built-in brightness controls (from the Action Center sidebar, keyboard hotkeys, and the Settings app) instead of using random DDC/CI apps from the Internet.

All of my monitors fully support Windows' VCP Monitor Configuration API (verified by using a VCP API developer tool) so I assume there must be some configuration option or setting in Windows that tells it to show or hide the brightness controls, but where is it?

Update: Based on my reading of the Windows HDK documentation for hardware brightness controls, it requires close cooperation of Windows' own "monitor driver" (monitors need drivers?) and the GPU's driver (NVidia, AMD, Intel, etc) with Windows: i.e. Windows' built-in brightness sliders seemingly always go through the GPU driver, as the expectation is hardware GPUs have control over integrated displays, so it doesn't seem possible for third-party applications to hook into this process.

Dai
  • 2,671
  • Laptop screens seem to support a different brightness control API, as DDC/CI APIs for example report unsupported status on a Lenovo ThinkPad..yet Windows is able to alter the brightness on the monitor. There should be just one set of APIs obviously.. kinda lame. – mms Nov 13 '18 at 03:44
  • @mms I remember my old Toshiba Tecra M4 could adjust its brightness using CreateFile(L"\\\\.\\LCD", FILE_ANY_ACCESS, 0, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL). See the brightness controller on this page: http://www.ookii.org/Software - does this work on your Lenovo? – Dai Nov 13 '18 at 04:50
  • Note if you have an NVIDIA graphics card you may be able to adjust brightness via NVDIA Control Panel -> Display -> Adjust desktop color settings -> Brightness – User Nov 04 '21 at 05:58
  • Built-in displays can use ACPI, WDDM, DPCD if not even dedicated drivers. – mirh Dec 21 '22 at 03:00
  • There ARE 3rd party apps that'll let you control brightness via DDC/CI, one is Twinkle Tray https://twinkletray.com/ I went down a similar rabbit hole, and am now using Twinkle Tray to control the brightness of my monitors.

    So considering it can control them, I find it hard to believe windows can't.

     – nabeelr Jan 08 '23 at 10:10

2 Answers2

0

Im using SunsetScreen app for desktop instead, it is a tiny lightweight portable app to control brightness and also many more like night light.

https://www.skytopia.com/software/sunsetscreen/

amymor
  • 35
  • This doesn’t answer my question, sorry. I’m asking about Windows’ built-in controls, I don’t want to use a third-party utility (because I already have a bunch of them). – Dai Sep 17 '23 at 04:07
0

I've been looking for the solution for days, so far no luck. However apparently it is possible to control the brightness of external monitors via Windows API. I have created a tiny tool in python that does that (lumiray). It's just a test under development but seems to work fine for a single monitor. If there is a way to set a regedit value somewhere to enable and hook the brightness slider to the app, it would be what you are looking for.

Shamsiddin Nabiev
  • 1
  • As it’s currently written, your answer is unclear. Please [edit] to add additional details that will help others understand how this addresses the question asked. You can find more information on how to write good answers in the help center. – Community Feb 06 '24 at 04:58
  • Are you selling computer programs who mess with the registry? – Dominique Feb 06 '24 at 07:45