LCD goes to sleep, but backlight stays on (always).

[Ground Loop]

I recently installed Gentoo Linux on the T43p, and it's working out very well. I have the console running in 1400x1050, and Xorg working fine too.

The one outstanding issue is that the LCD backlight does not go to sleep with the backlight. After the appropriate idle time, the LCD blacks out, but the backlight still remains lit, even after hours.

I know these things don't have an unlimited life, so I'd like to turn off the light along with the display, just like it does in WinXP.

I did some searching, and understand that I can turn off the backlight with the radeontool, which works fine. I've seen various hacks to tie radeontool into callbacks from the TPB buttons, or suspend scripts, but this seems much too disconnected from what I need.

Is there any easy way to make the backlight turn off anytime the LCD does? Anyone done it, or are we all waking up to glowing black screens?

Also, it does turn off when I close the lid, even though I have no special event for that or ACPI scripts. That's just the physical switch.