modprobe.conf, modprobe.d - Configuration file/directory for modprobe
Because the modprobe command can add or remove extra more than one mod
ule, due to module dependencies, we need a method of specifying what
options are to be used with those modules. /etc/modprobe.conf (or, if
that does not exist, all files under the /etc/modprobe.d directory)
specifies those options, as required. It can also be used to create
convenient aliases: alternate names for a module. Finally, it can
override the normal modprobe behavior altogether, for those with very
special requirements (such as inserting more than one module).
Note that module and alias names (like other module names) can have -
or _ in them: both are interchangable throughout all the module com
The format of modprobe.conf and files under modprobe.d is simple: one
command per line, with blank lines and lines starting with # ignored
(useful for adding comments). A \ at the end of a line causes it to
continue on the next line, which makes the file a bit neater.
The syntax is a simplification of modules.conf, used in 2.4 kernels and
alias wildcard modulename
This allows you to give alternate names for a module. For exam
ple: "alias my-mod really_long_modulename" means you can use
"modprobe my-mod" instead of "modprobe really_long_modulename".
You can also use shell-style wildcards, so "alias my-mod*
really_long_modulename" means that "modprobe my-mod-something"
has the same effect. You cant have aliases to other aliases
(that way lies madness), but aliases can have options, which
will be added to any other options.
Note that modules can also contain their own aliases, which you
can see using modinfo. These aliases are used as a last resort
(ie. if there is no real module, install, remove, or alias com
mand in the configuration).
options modulename option...
This command allows you to add options to the module modulename
(which might be an alias) every time it is inserted into the
kernel: whether directly (using modprobe modulename, or because
the module being inserted depends on this module.
All options are added together: they can come from an option for
the module itself, for an alias, and on the command line.
install modulename command...
This is the most powerful primitive in modprobe.conf: it tells
modprobe to run your command instead of inserting the module in
the kernel as normal. The command can be any shell command:
this allows you to do any kind of complex processing you might
wish. For example, if the module "fred" worked better with the
module "barney" already installed (but it didnt depend on it,
so modprobe wont automatically load it), you could say "install
fred /sbin/modprobe barney; /sbin/modprobe --ignore-install
fred", which would do what you wanted. Note the --ignore-
install, which stops the second modprobe from re-running the
same install command. See also remove below.
You can also use install to make up modules which dont other
wise exist. For example: "install probe-ethernet /sbin/modprobe
e100 || /sbin/modprobe eepro100", which will try first the e100
driver, then the eepro100 driver, when you do "modprobe probe-
If you use the string "$CMDLINE_OPTS" in the command, it will be
replaced by any options specified on the modprobe command line.
This can be useful because users expect "modprobe fred opt=1" to
pass the "opt=1" arg to the module, even if theres an install
command in the configuration file. So our above example becomes
"install fred /sbin/modprobe barney; /sbin/modprobe --ignore-
install fred $CMDLINE_OPTS"
remove modulename command...
This is similar to the install command above, except it is
invoked when "modprobe -r" is run. The removal counterparts to
the two examples above would be: "remove fred /sbin/modprobe -r
--ignore-remove fred && /sbin/modprobe -r barney", and "remove
probe-ethernet /sbin/modprobe -r eepro100 || /sbin/modprobe -r
Using this command, you can include other configuration files,
or whole directories, which is occasionally useful. Note that
aliases in the included file will override aliases previously
declared in the current file.
Modules can contain their own aliases: usually these are aliases
describing the devices they support, such as "pci:123...".
These "internal" aliases can be overridden by normal "alias"
keywords, but there are cases where two or more modules both
support the same devices, or a module invalidly claims to sup
port a device: the blacklist keyword indicates that all of a
particular modules internal aliases are to be ignored.
There is a generate_modprobe.conf program which should do a reasonable
job of generating modprobe.conf from your current (2.4 or 2.2) modules
Although the syntax is similar to the older /etc/modules.conf, there
are many features missing. There are two reasons for this: firstly,
install and remove commands can do just about anything, and secondly,
the module-init-tools modprobe is designed to be simple enough that it
can be easily replaced.
With the complexity of actual module insertion reduced to three system
calls (open, read, init_module), and the modules.dep file being simple
and open, producing a more powerful modprobe variant can be done inde
pendently if there is a need.
As a Debian-specific feature, files in /etc/hotplug/blacklist.d/ are
read and every non-comment line is considered as if it were the argu
ment of the blacklist keyword.
This manual page Copyright 2004, Rusty Russell, IBM Corporation.
09 August 2005 MODPROBE.CONF(5)