Compiling Kernel   «Prev  Next»
Lesson 5 Supporting module configuration
Objective Configure kernel modules.
Some modules require configuration information, such as the SoundBlaster module (sb), which accepts
  1. irq,
  2. dma, and
  3. io parameters.
Because modules might be loaded without human intervention, the /etc/conf.modules file stores default values for various modules' parameters.
When modprobe loads a module, it consults this file for appropriate defaults. Aliases for various modules also can be specified in the /etc/conf.modules file, as can shell commands to be executed when loading or unloading modules.
Every line in the /etc/conf.modules file specifies a directive, which is simply an instruction to modprobe when it consults this file. Directives begin with a keyword specifying their function, such as alias to alias names of modules or options to specify a module's options.

For example:
 pre-install pcmcia_core /etc/rc.d/init.d/pcmcia start
 alias eth0 tulip
 options sb io=0x220 irq=7 dma=0 mpu_io=0x300

The first line tells modprobe to run the /etc/rc.d/init.d/pcmcia start command before loading the pcmcia_core module.
The second line tells modprobe that references to the name "eth0" really refer to the tulip module.
Finally, the last line sets various options for the SoundBlaster modules.
For a full list of /etc/conf.modules supported syntax, check the man page for conf.modules.

The next lesson describes the pros and cons of rebuilding your kernel.

Kernel Modules - Quiz

Before moving on to the next lesson, click the Quiz link below to check your understanding of kernel modules and concepts.
Kernel Modules - Quiz