Brightness keys no longer working

[David Rosenstrauch <darose@xxxxxxxxxx>]

The screen brightness increase and decrease keys on my laptop seem to be 
no longer working.  They were definitely working a week or so ago, so 
I'm thinking some recent upgrade is responsible.

It's not that the keypress is registering and the app just doesn't 
brighten the screen.  But rather, that the keypress doesn't seem to be 
registering at all (i.e., when I try pressing it while using the "xev" X 
events tester app).  About a week ago, xev used to show a keypress event 
for something like "XF86BrightnessUp" or some such; now it shows 
nothing.  Anyone have any idea what the culprit might be?

Thanks,

DR