modprobe.conf(5) File Formats Manual modprobe.conf(5)
modprobe.conf -- 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
example: "alias my-mod really_long_modulename" means you can
use "modprobe my-mod" instead of "modprobe really_long_modu-
lename". 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 can't 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 command in the configuration).
options modulename option...
This command allows you to add options to the module module-
name (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
didn't depend on it, so modprobe won't 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 sec-
ond modprobe from re-running the same install command. See
also remove below.
You can also use install to make up modules which don't oth-
erwise 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-ethernet".
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 there's
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/mod-
probe -r --ignore-remove fred && /sbin/modprobe -r barney",
and "remove probe-ethernet /sbin/modprobe -r eepro100 ||
/sbin/modprobe -r e100".
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 support a device: the blacklist keyword
indicates that all of that particular module's 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.
This manual page Copyright 2004, Rusty Russell, IBM Corporation.