I have a hp pavilion g6 laptop. My keyboard has stopped working so I cannot use laptop keyboard to change the brightness. The issue is my brightness is set at 0 so I cannot see anything once ubuntu loads. I have attached an external keyboard via usb, I was wondering how can I change the brightness using the external keyboard. Is there a way. I cannot login or see anything once ubuntu is loaded its total dark on the login screen.

Any help is appreciated.