[Q] For the devs: possible to dim backlight by hacking PWM kernel code?
I'd like to use my N10 outdoors for astronomy. Mounted to a telescope, not just casual stargazing, so the screen needs to be really dark. Unfortunately, even with the brightness set to minimum, the background light from a totally black screen is still far too bright. The only way to fix this is to turn down the backlight, below the level allowed in Android. The raw hardware might allow this, or it might not.
Ok, before someone asks the obvious: I've already tried ScreenDim. On the N10 it cannot dim the backlight beyond what is already possible under Settings->Brightness. (Of course, it can also dim the display data, but that just destroys contrast without cutting back the leakage through the black pixels.) I emailed the author, and he says that his other app, RootDim, has the same limitation. So please don't suggest anything from the Play Store unless I've missed something here... and I almost certainly haven't.
I'm wondering if there's a kernel dev curious enough to look into the backlight PWM control and see whether there is room to decrease the brightness further. The higher-level control (used by ScreenDim) appears to be unsigned 8-bit, because the minimum is "0.4%". Perhaps more precision could be applied by hacking the relevant kernel driver? Going into a terminal and doing
ls -R /sys | grep backlight
which seems a promising place to start, but I don't know where to find the kernel code repository (and google searches weren't helping). Anyway, I've never done any android kernel hacking before and it would take me a while to come up to speed...