I have been running Ubuntu (64-bit) on my HP 6710b laptop (Core 2 Duo with integrated graphics) for several years, and the backlight brightness keys have always worked. Since I upgraded to Ubuntu 12.10 earlier today, those keys do not work any more.

The secondary function keys:

• Fn+F3: sleep; still works (and considerably faster than ever before!)
• Fn+F8: battery info; still works
• Fn+F9: reduce brightness; stopped working in 12.10
• Fn+F10: increase brightness; stopped working in 12.10

It may also be worth while mentioning that X does not appear to be receiving the brightness events at all, or at least not sending them out further. (This I detected with a key logger I wrote for a Uni project, which uses X's Record extension; it is informed of the sleep and battery info keystrokes, but doesn't receive the brightness ones at all.)

In the mean time, I know that I can use the Brightness & Lock settings screen to alter the brightness. (Wow! I can suddenly make my backlight darker than I could before—I can go right down to turning the backlight off, something I couldn't do before... but this model has a fairly dim screen, so I don't expect to use that much, if ever.)

How can I get the brightness keys working again?

This question is probably strongly related to I can't control my Brightness in HP Compaq 6710s.