Fix Screen Brightness Control bug on Windows 10

Some older laptops have issues after upgrading to Windows 10 when it comes to graphics due to drivers not getting patched with recent bug fixes. Certain older ATI Radeon graphics in particular have issues with brightness control not working on Windows 10 at all.

 

Before attempting anything else it’s a good idea to make sure that both Windows and system drivers are up to date. Many fixes have been suggested such as making sure that the display device is enabled in Device Manager or enabling Adaptive Display brightness in Advanced Power Options menu. In most cases both of these options should already be configured properly by default. In many cases the fix may lie hidden in registry settings.

 

Hit start and type in regedit. Run command option should appear for regedit, hit enter to launch it. Alternatively it can be launched by typing regedit.exe in the run window.

 

Next navigate to HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\Class\{4d36e968-e325-11ce-bfc1-08002be10318} registly location on the left and select 0000 entry.

A better option is to go to Edit -> Find then paste {4d36e968-e325-11ce-bfc1-08002be10318} and hit find to skip the tedious navigation.

 

On the right find KMD_EnableBrightnessInterface2 and possibly MD_EnableBrightnesslf2. Depending on exact hardware and software registry entries can be different so if one is missing it doesn’t mean it won’t work. On the other hand there may also be other entries that may need to be changed for this fix to work. There is also always the possibility that no amount of registly editing may work at all, all one can do is try. Double click or right click and then Modify for each entry to bring up an edit window. Change the value from 1 to 0 and hit ok for each entry to save the changes.

Now reboot the system, cross your fingers as is often neccesary in Windows and test the brightness controls.