What if the Win10 screen brightness cannot be adjusted?

There is user feedback to upgrade the system to Win10, the screen brightness can not be adjusted, especially after upgrading from Win7, Win8.1 old version to Win10, it is more prone to some strange problems. Microsoft's official help center also gives a solution to the problem that Win10 screen brightness cannot be adjusted.
Problem performance:
• First, try to uninstall the discrete graphics driver in safe mode. After uninstalling, the screen brightness can be adjusted freely;
• Secondly, check the device manager and find that the discrete graphics driver is not running. Installation, still unable to adjust the brightness freely after reinstalling.
Workaround:
• Right click on “Start Menu”——Select“Run”——Enter“regedit”, press Enter to open the registry, and then expand:< Br>{HKEY_LOCAL_MACHINESYSTEMControlSet001ControlClass{4d36e968-e325-11ce-bfc1-08002be10318}
• Modify the KMD_EnableBrightnessInterface2 key value in 0000 and 0001 to 0.

In addition, if there is no such key value, create a new one, the type is DWORD. If there is no 0001, just modify the key value in 0000.
• Restart the device after the modification is complete, and then try to adjust the brightness.