Originally Posted by TobiSGD
You don't need working drivers to see a device (otherwise we really would have a problem with all the people here with wireless problems), all you need is an up-to-date database for lspci/lsusb. But of course this only helps to determine which hardware is present, but not which driver is needed for that hardware, localmodconfig and and localyesconfig therefore are only looking which drivers are currently loaded and create a config file for those drivers.
That's actually not very bad since it's excellent for situations like debian unstable or experimental:
e.g. I download 3.8.3 from experimental debian, it has EVERYTHING as a module (or built-in when they can't), so there a method like that would make a tiny .config compared to before.
Right now it's extremely gruesome because you have to go through around 40minutes+ in most systems to recompile a kernel for your processor, CFLAGS, or other minor different settings.
The alternative of going manually is also gruesome not so much because it's impossible but you can't really do it once. After 6 months it might need another trimming since the structure of the kernel itself might change (it has happened a lot especially after major 2.x releases).
Though of course I don't know if that method is quirky (e.g. creating problems with built-in features etc.), I haven't seen it in action.