Firstly, I'm running Gentoo amd64 on an HP Pavilion dv6
, with the ATI drivers (11.7, but I've had the same problems since 11.5), and a 3.0.1 vanilla kernel (again, problems since 2.6.37). I only got the laptop a few months ago, so I haven't tried any newer drivers.
I have mucked around with the kernel config, and put in all the obviously backlight-related options, but I can't work out how to get backlight control working. At the moment, nothing shows up in /sys/class/backlight/; it's just an empty directory. The backlight buttons don't do anything, and when it boots, the laptop just sits at full brightness, which makes it very difficult to use when not plugged in.
I know the backlight works únder Linux, because it has responded properly in OpenSUSE, Fedora 15, and Ubuntu.
So, my question, what do I need to do to enable backlight support? Apart from this issue, and the fingerprint-reader and some multimedia buttons, the hardware runs Gentoo flawlessly, and it's a shame to have such a seemingly simple problem persist.