The order in which modules are processed by the depmod command can be altered on a global or per-module basis. This is typically useful in cases where built-in kernel modules are complemented by custom built versions of the same and the user wishes to affect the priority of processing in order to override the module version supplied by the kernel.
The format of depmod.conf and files under depmod.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.
By default, depmod will give a higher priority to a directory with the name updates using this built-in search string: "updates built-in" but more complex arrangements are possible and are used in several popular distributions.
For example, it is possible to override the priority of an updated test module called kmp by specifying the following command: "override kmp * extra". This will ensure that any matching module name installed under the extra subdirectory within /lib/modules (or other module location) will take priority over any likenamed module already provided by the kernel.
This manual page Copyright 2006, Jon Masters, Red Hat, Inc.