keyboardmacos
I recently had to reinstall Lion. Now, when I boot the keyboard is not backlit when at the login screen. It used to be backlit when at the login screen.
I'm using a Macbook Air 11" July 2011 model. In System Preferences I have the checkbox: Automatically illuminate keyboard in low light checked. The setting for Turn off when computer is not used for: is set at Never.
The following works.
System Preferences -> Login -> Login Options -> Check Enable Show Input menu in login window
I don't know if it's Lion or a hardware feature, but on my MacBook Air, the system changes the keyboard lighting (and screen brightness) depending on the ambient brightness, which is detected by a sensor near the iSight lens at the top of the screen. In bright surroundings, the keyboard lighting is disabled and pressing F5 or F6 does nothing.
Best Answer
It appears that the problem is related to FileVault. When I turned FileVault off and rebooted in safe mode the problem went away. I could change the brightness of the screen and the keyboard at the login screen. Volume controls worked too. Now that I've turned FileVault back on the problem is back.