Studio 1458 Screen Brightness Control disabled after hibernation/sleep

 I have lost my screen brightness control and screen is set to maximum brightness. When I restart my laptop it gets fixed but as soon laptop wakes up from standby or hibernation the screen returns to maximum brightness. FN+F4/F5 is not responding in changing the brightness too, even at the power option also cannot change the brightness.

the only solution is to restart the machine.

Kindly help.