I recently upgraded my lenovo ideapad 100 with Intel Pentium N3540 and Intel HD Graphics from windows 8.1 to windows 10 and my screen brightness control is reversed (Reduces as i increase from 25%-100% and vice versa) after a shut down and startup but when i reeboot the system it start working normally
After searching google for the solution, i found out that the problem is unique to Intel Pentium N3540 Processor and it HD Graphics Adapter.
The best fix i found was to Turn Off Windows Fast Boot Option so that windows can load the driver properly
And i really want to turn back on this fast boot option