M6600: Can't adjust screen brightness? Try this.

I thought about posting this in the M6600 owner's thread, but it's now approaching 1100 posts, and I think this is going to be a relatively common issue that people are going to be looking for a solution to, so... It'll be easier to find it in a google search or whatever if it gets its own thread.

I got my M6600 on Friday. The first thing I did was to throw the RAM, SSD and HDD upgrades and install Windows 7 Ultimate from the included restore disk.

I used the latest reference drivers from Intel and nVidia for the chipset, the wlan card, the HD3000 graphics and the nVidia graphics. All the other drivers came from Dell. I installed some of the Dell software-controlpoint, a few other things.

Having done all that, I found that I could not adjust the backlight brightness within Windows. I could adjust it in the BIOS and it would retain its setting into Windows, but it was not adjustable after Windows loaded. Attempting to adjust it would cause the OSD to pop up and show the current brightness level, but it wouldn't adjust, and adjusting it using the slider in the power management menu had no effect.

I tried uninstalling and reinstalling all of the various Dell utilities, to no avail. What fixed it? Installing Dell's drivers for the Intel IGP.

So yeah. If you can't adjust the brightness of the screen on your Quadro-equipped M6600, and you've got the controlpoint utility installed, consider installing (or reinstalling) the dell-supplied driver for the Intel IGP.