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This page is an introduction and FAQ for Modules. It is not intended to replace official documentation (listed at the bottom of the page).

• Contents

  1. Kernel Modules
     1. Automatic loading of modules
     2. Alias
     3. See Also

Kernel Modules

Under Debian, the module can be installed from three different kind of sources :

• Upstream (Linux) Kernel modules : Those are shipped in the linux-image-2.6 kernel packages.

• Extra modules, that's aren't in Linux kernel. Those are usually built using module-assistant. The Available modules can be listed by running apt-cache rdepends module-assistant. Note: some of those packages are in contrib, or non-free sections.

• Others, like Third party, Proprietary and other or Binary blobs modules... You should not install such modules on your system.

Automatic loading of modules

• Nowadays, most modules related to hardware support should be automatically loaded, thanks to udev and modules alias that are hardcoded in kernel modules (see the alias fields in modinfo snd-hda-intel output).

If you want to get a module to autoload when a device is accessed you can often add a file to /etc/modutils and run update-modules to generate /etc/modules.conf. When the kernel receives a request to open a device file that it does not have capabilities for it issues a request to modprobe for the module 'char-major-n' or 'block-major-n' depending on whether the device is a character or block device, and the device's major number, n. For example, my sound devices have major number 14, and my sound module is emu10k1 so added the alias below to my /etc/modutils directory.

$ ls -l /dev/dsp
crw-rw----    1 root     audio     14,   3 Jul  5  2000 /dev/dsp

$ cat /etc/modutils/sound
alias char-major-14 emu10k1

Alias

This file links specific Kernel module names to the service names the kernel knows (aliases).

As a very simple example, it could link the service eth0 to the kernel driver module for the particular ethernet card you installed in your computer.

The alias directive can be used to give alias names to modules. A line in /etc/modules.conf that look like this:

 alias iso9660 isofs 

makes it possible to write modprobe iso9660 although there is no object file for such module available.

See Also

• ModulesAll - Full List of Kernel Modules for the Debian's Linux Kernel.

• KernelModuleBlacklisting - Prevent a module from beeing automatically loaded.

• ModuleAssistant - Build extra modules.

• initramfs - aka Loading modules at boot time, before te root file system is mounted.

• Manpages :

  • modprobe, lsmod, modinfo and update-modules

  • ...and also insmod, depmod, rmmod, depmod.conf, modules, modules.dep and modprobe.conf

CategoryKernel