The button that is supposed to toggle the ambient light sensor on HP EliteBooks 8440p and 8460p per default switches off the touch pad. That is because
0x33), which is the ambient light button, is incorrectly mapped to
KEY_TOUCHPAD_OFF (keycode 193) in kernel.
To remap the scancode to another keycode, you can use
setkeycodes. An appropriate choice for a target keycode could be
XF86Launch1, keycode 148) which can be easily reconfigured in KDE or any other desktop environment to run any custom command.
Run the following command as root to remap
# setkeycodes e033 148