Laptop brightness adjustment not working AMD graphics card

Solution 1:

This issue affects lots of AMD cards and drivers. The fix is as follows.

1. Go to the registry editor (start > regedit)
2. Change both of the following registries to 0

KMD_EnableBrightnessInterface2

MD_EnableBrightnesslf2

The registry path can vary slightly, but it will be one of the following or something similar. To find they key, I did a search through the registry.

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\Class{4d36e968-e325-11ce-bfc1-08002be10318}\0000

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class{4d36e968-e325-11ce-bfc1-08002be10318}\0001

3. Reboot.
4. If it still doesn’t work, in Device Manager, disable your video adapter and re-enable. Make sure your PnP monitor is still enabled.

Note: In my case MD_EnableBrightnesslf2 didn’t exist. In this case just changing KMD_EnableBrightnessInterface2 to 0 will fix the problem.