Dynamic Kernel Module Support

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From Wikipedia:

Dynamic Kernel Module Support (DKMS) is a program/framework that enables generating Linux kernel modules whose sources generally reside outside the kernel source tree. The concept is to have DKMS modules automatically rebuilt when a new kernel is installed.

This means that a user does not have to wait for a company, project, or package maintainer to release a new version of the module. Since the introduction of Pacman#Hooks, the rebuild of the modules is handled automatically when a kernel is upgraded.


Install the dkms package and the headers for your kernel (for the default linux kernel this would be linux-headers).

A good number of modules that lie outside the kernel source tree have a DKMS variant; a few are hosted in the official repositories, most are found in the AUR.


Though the rebuild of the DKMS modules is usually seamless during a kernel upgrade, it may still happen that the rebuild fails. You should pay extra attention to the Pacman output. This applies in particular if the system relies on the DKMS module to boot successfully and/or if you use DKMS with a custom kernel not in the Official repositories.

To deal with changes in the kernel, fix bugs, or add necessary features consider upgrading the DKMS package before rebooting.


Usage for invoking DKMS manually.

Tab-completion is available by doing:

# source /usr/share/bash-completion/completions/dkms

List modules

To list the current status of modules, versions and kernels within the tree:

# dkms status

Rebuild modules

Rebuild all modules for the currently running kernel:

# dkms autoinstall

or for a specific kernel:

# dkms autoinstall -k 3.16.4-1-ARCH

To build a specific module for the currently running kernel:

# dkms install -m nvidia -v 334.21

or simply:

# dkms install nvidia/334.21

To build a module for all kernels:

# dkms install nvidia/334.21 --all

Remove modules

To remove a module (old ones are not automatically removed):

# dkms remove -m nvidia -v 331.49 --all

or simply:

# dkms remove nvidia/331.49 --all

If the package dkms is removed the information regarding previous module build files is lost. If this is the case, go through /usr/lib/modules/KERNELVERSION-ARCH and delete all files and directories no longer in use.

DKMS package creation

Here are some guidelines to follow when creating a DKMS package.

Package name

DKMS packages are named by appending "-dkms" to the original package name.

The variable $_pkgname is often used below $pkgname to describe the package name minus the "-dkms" suffix (e.g. _pkgname=${pkgname%-*}). This is useful to help keep similarities between the original package PKGBUILD and the DKMS variant.


Dependencies should be inherited from the original version with dkms added and linux-headers removed (as it is listed by the dkms package as optional).

Build source location

Build sources should go into (this is the default build directory for DKMS):


In the package directory, a DKMS configuration tells DKMS how to build the module (dkms.conf), including the variables PACKAGE_NAME and PACKAGE_VERSION.

  • PACKAGE_NAME - the actual project name (usually $_pkgname or $_pkgbase).
  • PACKAGE_VERSION - by convention this should also be the $pkgver.


The sources can be patched either directly in the PKGBUILD or through dkms.conf.

Module loading automatically in .install

Loading and unloading modules should be left to the user. Consider the possibility a module may crash when loaded.

Also, please note that you do not have to call depmod explicitly to update the dependencies of your kernel module. Pacman is now calling DKMS dkms install and dkms remove automatically as hooks. dkms install is making sure depmod is called at the end of its process. dkms install depends on dkms build (to build the source against the current kernel), which itself depends on dkms add (to add a symlink from /var/lib/dkms/<package>/<version>/source to /usr/src/<package>).


Here is an example package that edits dkms.conf according to the package name and version.


# Maintainer: foo <foo(at)example(dot)org>
# Contributor: bar <bar(at)example(dot)org>

pkgdesc="The Example kernel modules (DKMS)"
arch=('i686' 'x86_64')
md5sums=(use 'updpkgsums')

prepare() {
  cd ${_pkgbase}-${pkgver}

  # Patch
  patch -p1 -i "${srcdir}"/linux-3.14.patch


package() {
  # Install
  make DESTDIR="${pkgdir}" install

  # Copy dkms.conf
  install -Dm644 dkms.conf "${pkgdir}"/usr/src/${_pkgbase}-${pkgver}/dkms.conf

  # Set name and version
  sed -e "s/@_PKGBASE@/${_pkgbase}/" \
      -e "s/@PKGVER@/${pkgver}/" \
      -i "${pkgdir}"/usr/src/${_pkgbase}-${pkgver}/dkms.conf

  # Copy sources (including Makefile)
  cp -r ${_pkgbase}/* "${pkgdir}"/usr/src/${_pkgbase}-${pkgver}/


MAKE[0]="make --uname_r=$kernelver"
CLEAN="make clean"


Now pacman has DKMS hooks implemented, you do not have to specify DKMS-specific configuration in your .install file. Calls to dkms install and dkms remove will be automatic.

See also