Configuring the 2.6 Linux Kernel

An anonymous reader writes "This article is the first in a series by William von Hagen on using the new Linux 2.6 kernel, with a special emphasis on the primary issues in migrating existing drivers, applications, and embedded Linux deployments to a Linux distribution based on the 2.6 kernel. Bill is the author of Linux Filesystems, Hacking the TiVo, SGML for Dummies, Installing Red Hat Linux 7, and is the coauthor of The Definitive Guide to GCC (with Kurt Wall) and The Mac OS X Power Users Guide (with Brian Profitt)." This looks to be a good series for anyone planning to migrate to Linux 2.6, and having done just that myself, I'll attest to wanting more documentation along the way.

Default

[Grey_14]

Whats with the default config for the kernel, it's not blank, it's a specific setup that looks like it's for a P4 with a specific network card and chipset, shouldnt the kernel config be bare? this is referring to source downloaded directly from kernel.org,

Usability?

[polyp2000]

Is the 2.6 kernel "Usable" yet? By this I mean getting obscure hardware to work such as my USB Midi Interface, and what about proprietary drivers such as Nvidia's, will existing code compiled for 2.4 kernel work? or will you have to recompile stuff (IPTables for example). Im running a gentoo box. I've been toying with updating the kernel to 2.6 and I've been hearing that there are a lot of radical changes to the kernel, the performance enhancements are very exciting to say the least. But what kinds of headaches am I going to have with a real world (used as a desktop as well as a server) system?

KernelWiki

[Bruha]

I've considered setting up a wiki for the Kernel to give people a place to file what they've learned about it and share with the general public. Anyone think this would help anyone?

is it so much different than 2.4?

[locknloll]

I've only recently started using Linux on a day-by-day basis, and after installing Debian unstable I switched directly to 2.6, without ever compiling a 2.4 kernel. That worked without a hitch, so now I'm wondering if the difference is so big. I still have an old Pentium I around the house, and I'm thinking of making this one a firewall/IDS... and so far I'm not sure if 2.6 was a little overkill for that one...

2.6 breaks KVM support

[Bill Hayden]

As far as I can tell, there is no way to use a KVM with kernel 2.6 and still have mouse wheel support. It works until you switch away and back to Linux, at which point the mouse goes completely nuts and cannot be revived. Back in 2.4, there were two hacks to revive the mouse in this situation (switch VCs, or set the mouse protocol in X to "AUTO") but neither of these work in 2.6. Windows, needless to say, has no problems. You can supposedly pass a psmouse.noext parameter to the kernel at boot time to fix the craziness, but a) this would remove mouse wheel support, and b) I never got it work anyway. If you know a workaround, please post!

Configure your own kernel

[runen]

The problem with building your own kernel is that you will always make it as slim as possible. Then each time you buy a new piece of hardware (USB-mouse, SATA hd, etc) you'll need to build it again (and you've thrown away the original .config of course :). Is there a configure everything (besides what's been specified as built-in) as modules?

Re:Usability?

[Anonymous Coward]

(A +5 Troll ? ..... anyway...)

AFAIK, for drivers, if it works in 2.4, it's supposed to work in 2.6.

iptables support is pretty much the same aside from having a gazillion new options to play with, and of course you'll need to recompile the iptable support in the kernel (what else? you're compiling the kernel anyway)

Well, as far as I've been using 2.6, it's very much "usable", there aren't any show-stopping problems that I've encountered on any 2.6.0 + kernels of yet, and it's quite stable. (I have a 32 day uptime 2.6 server (*) with non-trivial loads) though the more sophisticated features (eg. LVM/RAID) might need some polishing.

(*): It's basically a testing/miscellaneous-use server, the production servers will probably have to wait a few months.

More binaries needed

[inf0mike]

I think this will turn out to be a great series of white papers helping people get to grips with the process of configuring and compiling their own kernels, but I have to say that I think there would be faster progress on new kernels if the was some central repository of precompiled binary packages for the major distros throughout the development cycle.

The truth of the matter is that now linux is gaining wider acceptance, the community is filling up with more and more noobs and we should be doing more to help them understand the "new" (to them) technology. We also need to remember that not everyone who wants to use the software needs to be some sort of guru.

This article is a great start to moving more people to the new code quicker, but regular up to date debs/rpms for all the current distributions will push that long even faster. I know someone will probably post saying "but there are packed versions for xxxx at somewhere.org", but they are often difficult to find for the noobs who just don't know where to look.

That's great

[Apreche]

I didn't know about xconfig before! I really have to spruce up my install. I'm still using kernel 2.6.0 and I should probably up it to 2.6.2. My problem is I use gentoo and I have to configure the kernel manually. I know HOW to do it as in what make commands to issue in order to get a binary kernel out of the thing. And how to put the kernel in /boot and point my lilo at it. What I'm not always sure on is exactly which configure options I want on and off. The important ones are obvious. Yes I have an athlon. Yes I need my nfornce network card, emu10k1, silicon image sata, pre-emptible kernel etc. etc. But a lot of them I just have no clue. Some options have useful help messages like "if you don't know, just say Y (or N) it wont slow you down". But there are still a zillion modules and options in there that I have no clue if I should use Y M or N.

We should make a repository of hardware configurations and which options should be turned on depending how you will use it. People should just say hey, I got this machine here with this hardware. I'm using it as a web server, and this is my kernel config. If enough people put there configs in, then people like me could find others with similar or identically matching hardware and use those configs. I'm sure it would also bring to light better configs for most people. I'm sure there's some guy out there not selecting a certain option who should be. And if he posts his config online some geek will be sure to point it out to him.

Re:2.6 breaks KVM support

[Espectr0]

Could you please point me to the click-n-drool option button in Windows2000 that allows me to enable command-line completion?

I dont know about w2k, but winxp supports command-line completion out of the box. Just hit tab as you would on linux

Re:Do it the easy way : Get Manadrake 10-beta2

[ktanmay]

Let's see, apt-get install kernel-bla bla and then there's emerge sys-kernel/development-sources so if we fill in the bla bla, gentoo's the shortest.
But wait I think there's also emerge gentoo-sources-dev

Re:They need a tutorial on this stuff?

[atomic-penguin]

If you compile /proc/config support in the 2.6 kernel you can

`zcat /proc/config.gz > /path/to/2.6.x/.config`

You have your old config in place, I used it to upgrade from 2.6.1 to 2.6.2 very handy indeed.

Re:is it so much different than 2.4?

[sparrow_hawk]

I'll second that. I'm running a Pentium III 667MHz with hardware specs pretty much in line for a system of that vintage. My sister has an AMD Athlon 2200+, decent specs. My system is running 2.6.0, hers runs Windows XP and 2.4.22 (she likes the games on Linux :). Care to guess which system *feels* faster?

It's mine. Even when I'm compiling the latest kernel or listening to MP3s or running SETI@Home, or even doing all three at once, I have nary a skip or a hitch. The mouse and keyboard stuff is always smooth, and I never have to wait for my system to respond because the processor is tied up. 2.6 rocks -- Linux has extended the usable life of this system by *years*...