I use a Macbook 7,1 and I do not have this issue. Perhaps this issue is resolved?
- bug#22952: MacBook2,1 brightness control requires root pr... Albin
- bug#22952: MacBook2, 1 brightness control requires r... Ludovic Courtès
- bug#22952: Macbook2,1 brightness control requires ro... Joshua Branson
- bug#22952: Macbook2, 1 brightness control requir... Ludovic Courtès