Can not reduce the Screen brightness since the update 25may

I updated my laptop this afternoon and I noticed I could not reduce the screen brightness so while I write this thread Im wearing sun glasses so avoid getting blind. 
I have tried to use the keyboard shortcuts to reduce and increase the brightness and they don't work. Until yesterday they were working fine ( when i shutted down the computed it started to updating and today finished ) and I also tried to use the pannel control to change the brightness in my Energy options and it isn't working aswell.
I would appreciate some assistance to resolve this issue.