Basic gentoo questions

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belrpr · Post by **belrpr** » Sun Nov 19, 2006 11:22 pm

Hi,

I am quite good gentoo user but I still don't understand some basic gentoo options.

Does genkernel use the use flags too?
Anyone has a good guide to compile your kernel manual without over doing stuff. Like a basic config which every system needs and then I could add my hardware options to it?

What is the pro for genkernel and the downsides of it?

Thanks in advance.

DocReedSolomon · Post by **DocReedSolomon** » Sun Nov 19, 2006 11:39 pm

in general:
genkernel puts a lot of stuff in, to make most of the users happy.

in general it does not hurt, because most of the stuff is compiled as modules, and those are not loaded anyway if they are not needed.

finetuning your kernel depends on your hardware and needs,
do this "step by step" by running "make menuconfig" in /usr/src/linux.
not much different from SuSE or any other distro.

HTH

PS: USEflags have nothing to do with kernel compiling at all.

PaulBredbury · Post by **PaulBredbury** » Mon Nov 20, 2006 1:26 am

Modules are a pain because you still need something which loads the modules - otherwise, they are unavailable. Thankfully, programs are getting better at doing this automatically, e.g. xorg will (shock horror) load the nvidia module if it finds that it needs the nvidia module, rather than dying in a heap.

This is why it is better to compile your own kernel, with the options compiled in that you know you want, and everything else excluded so that they can't mess up or bloat your system.

jeanfrancis · Post by **jeanfrancis** » Mon Nov 20, 2006 1:56 am

PaulBredbury wrote:This is why it is better to compile your own kernel, with the options compiled in that you know you want, and everything else excluded so that they can't mess up or bloat your system.

Got a question... is there any advantage of using any option as a module, when I know that I will want it all the time? Some persons say to use as modules when it is possible... I wonder why.

eltech · Post by **eltech** » Mon Nov 20, 2006 2:02 am

jeanfrancis wrote:
PaulBredbury wrote:This is why it is better to compile your own kernel, with the options compiled in that you know you want, and everything else excluded so that they can't mess up or bloat your system.
Got a question... is there any advantage of using any option as a module, when I know that I will want it all the time? Some persons say to use as modules when it is possible... I wonder why.

I would say that most suggest including myself to compile into the kernel if you need it all the time. make it static ..

jmbsvicetto · Post by **jmbsvicetto** » Mon Nov 20, 2006 2:02 am

Hi.

jeanfrancis wrote:Got a question... is there any advantage of using any option as a module, when I know that I will want it all the time? Some persons say to use as modules when it is possible... I wonder why.

In my opinion, the best examples of when/why one should use a driver as a module, instead of compiling it in the kernel, are with the network drivers and the sound card drivers. Most network drivers seem to work only as modules or to only allow to set some options if run as modules. ALSA seems to run better if the drivers are built as modules instead of in the kernel. Moreover, if you want to restart the alsa system, you should have the driver built as a module.

PaulBredbury · Post by **PaulBredbury** » Mon Nov 20, 2006 2:07 am

jmbsvicetto wrote:Most network drivers seem to work only as modules

Sounds like voodoo. I've not heard that.

to only allow to set some options if run as modules

Set the options in /boot/grub/menu.lst, e.g.:

Code: Select all

kernel /boot/kernel root=/dev/sda1 panic=30 vga=775 usbhid.mousepoll=2

That sets the mousepoll option for the usbhid "module" (compiled-in).

jmbsvicetto · Post by **jmbsvicetto** » Mon Nov 20, 2006 2:51 am

PaulBredbury,

you won't need to search for long before you find a post on these forums where the solution to someone's problem with the network was to compile the network drivers as a module instead of compliing it in the kernel. About the options I meant options for the network modules. The following was extracted from /usr/src/linux/Documentation/networking/bonding.txt

It is recommended that you configure the
driver as module since it is currently the only way to pass parameters
to the driver or configure more than one bonding device.

onlinepancakes · Post by **onlinepancakes** » Mon Nov 20, 2006 4:04 am

Iv used Genkernel on my last two kernels (2.6.17-R7 and 2.6.18-R2) and it worked excellent with them. None of them had any issues at all. I also like the module way better. Havn't had any issues with them at all. Same goes with having Alsa built into the kernel rather than installing it myself. If you want to use Genkernel then I recommend it. Works like a charm.

belrpr · Post by **belrpr** » Mon Nov 20, 2006 8:33 am

Does genkernel still optimize program using the flags?

96140 · Post by **96140** » Mon Nov 20, 2006 10:11 am

Here are some official documents to get you started:

Genkernel Guide

Gentoo Kernel Configuration Guide

Crooksey · Post by **Crooksey** » Mon Nov 20, 2006 12:44 pm

The Pro's of genkernel is that it compiles everything you need, sometimes more.

Downside, can install a module that may not work, like a framebuffer, then it isnt easy to remove it.

Genkernel also copys your new kernel and initramfs files to /boot, so you only need to change the numbering in grub.conf.

welp · Post by **welp** » Tue Nov 21, 2006 1:12 pm

If you're building your own kernel, you'd generally want to build everything in. There are, as jmbsvicetto said, notable exceptions, such as the ALSA drivers and NIC drivers (although I always build mine in

)

I'd suggest you take a nice look at the links nightmorph posted, as well as the Gentoo ALSA Guide for configuration of your sound card.