I've asked this on IRC and the forums, but I'm not getting any further. Maybe I'm asking the wrong question or misunderstanding the few replies I get, but allow me to pose my question on the mailing list as well.
Over the last few years, I have been compiling kernels for well-defined sets of hardware, i.e. the systems I myself was working on. The items and devices I knew I had and needed were compiled in-kernel, some optional things as modules (that is, the more "functional" modules like file systems or support for Ethernet bridging, not the "hardware" modules). I knew about udev, and primarily thought of it as the program that could enforce persistent naming, heck, it could even rename network interfaces from the standard eth0 to something more meaningful. How cool! I recently found myself in a new and unexplored situation: I needed a generic kernel/module combination (precompiled) that would work on a variety of hardware in the x86 architecture, and especially a way to load the right modules. I always assumed there would be some kind of magic at work, but I guess there isn't. First idea: genkernel. Never used it before, but it seemed to work ok. The initrd generated by genkernel works with busybox's mdev. The net effect seems to be that every driver module (I noted IDE and SATA chipsets I never even heard of) in the initrd is loaded, relevant or not, and stays loaded. Ok, that'll probably work, but why bother creating modules, if I still use them all. And sure, I could unload most of them, but I don't want to bother my users with that. And it seems kind of inefficient, I mean, I wouldn't expect a 2009 Linux system to work like that. Second idea: manual initramfs creation. Very insightful and a recommended exercise. Problem: I have no idea how to handle the loading of modules the way I want. Questions: Should I use udev instead of mdev in the initrd? Would that make a difference? Why doesn't genkernel use udev too then? Does udev do any module loading or does it just act upon device file creation (meaning the relevant module is already loaded)? Somebody on IRC coined the term "hotplug", but the hotplug ebuilds have version names beginning with 2004. The elogs of those ebuilds talk about modules loaded at boot (yay!) and something called "coldplug", but coldplug is blocked by recent udev versions (aww!). So maybe udev does have the capability of loading relevant modules? Maybe I'm expecting too much, maybe I'm confusing device drivers with the genericity of what a module is, maybe I haven't read the right man pages or googled the right keywords. I would just really like someone to give me a clear explanation :-) Thanks in advance, Kobboi
