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Kernel configuration

How to configure, compile and install a Linux kernel


  1. Selecting kernel
  2. Installing the kernel
  3. Configuring the 2.4.xx kernel
  4. Compiling the kernel


1. Selecting kernel

Recommended kernel these days is 2.4.23 from http://www.kernel.org/ . The original kernel suits most people.

Use >= 2.4.23 or make sure your kernel has the latest security patches.

There are numerous patchsets of the stable vanilla kernel, the most popular are:

2.4

  • sys-kernel/usermode-sources the User Mode Linux kernel "User-Mode Linux is a safe, secure way of running Linux versions and Linux processes. Run buggy software, experiment with new Linux kernels or distributions, and poke around in the internals of Linux, all without risking your main Linux setup."

2. Installing the kernel

Unpack a nice kernel into /usr/src. Grab one from http://www.kernel.org/.

Then make (or edit) two symlinks to the kernel:

  ln -s /usr/src/your-kernel /usr/src/linux
  ln -s /usr/src/your-kernel /usr/src/linux-2.4

Now 'prepare' kernel (you only have to do this once. Note: This will delete configuration files, if you have any):

  cd /usr/src/linux
  make mrproper

3. Configuring the 2.4.xx kernel

You must configure the kernel for your system if you want optimal performance.

You can use any of these ways of configuring the kernel:

make oldconfig Use when upgrading kernel, only asks if new options
make menuconfig Console-type configuator
make xconfig XFree kernel configurator

It is generally a good idea to compile more than less modules. Entering 'm' does not mean that the module is enabled, only compiled.

Important Settings include:

3.1. USB

  USB
  USB support  --->
  USB verbose debug messages
  USB-to-USB Networking cable device support (EXPERIMENTAL)

3.2. Sound Card support

  Sound
  Sound  --->
  Sound card support

ALSA: Turn everything else in this section off (N) to use the alsa drivers .

OSS: y or m for any sound cards you have and may want.

3.3. Hardware sensors (lm-sensors) support

To be able to compile and use the hardware sensors monitoring program lm_sensors (shows your CPU and chipset temperature) you will need

  Character devices  ---> 
   I2C support  --->

And in this menu you must select the following as modules

   <M> I2C support
   <M> I2C device interface
   <M> I2C /proc interface (required for hardware sensors)    

The lm_sensors will not build if you compile this into your kernel by selecting Y.

//Common problems: If you compiled your kernel wrong and compiled the i2c package required by lm-sensors you must re-install this package before installing lm-sensors//

3.4. Make sure you actually save your config..

Remember: Do SAVE your config! You can even edit your kernel using KDEs kcontrol . It is wise to back up your kernel configuration from time to time:

  mkdir Config-backups
  cp .config Config-backups/current-config

4. Compiling the kernel

To compile your kernel, run:

  make dep && make clean bzImage modules modules_install

Your new kernel is now placed in /usr/src/linux/arch/i386/boot/bzImage. Copy this to your /boot partation.

Gentoo notice: /boot is not mounted by default. You must mount it yourself before copying the new kernel image.

  cp /usr/src/linux/arch/i386/boot/bzImage /boot

It's a good idea to backup your old kernel image with

  mv /boot/bzImage /boot/bzImage.old

and have both images available in your boot-loader.

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