Suppose I want to reverse engineer all of my laptop's power saving features and write drivers for them or whatever it is that Linux needs to work properly. How do I begin? I managed to get as far as dumping ACPI DSDT but I couldn't figure out where to go from there.

I got all the extra USB features working. It should be possible to support everything else too. If I learn this I'll add support for all the laptops I buy in the future too.