z·eeki·sh

need the following kernel modules before it’ll show up in fdisk -l:

sdhci_pci (depends on sdhci)
mmc_block (depends on mmc_core)

It is amusing to read the description of the mmc_block module though

This selects the disabler for the Ricoh MMC Controller. This proprietary controller is unnecessary because the SDHCI driver supports MMC cards on the SD controller, but if it is not disabled, it will steal the MMC cards away – rendering them useless. It is safe to select this driver even if you don’t have a Ricoh based card reader.

The salient point: just play with files inside /etc/modprobe.d/, as everything else is meant for backward compatibility.

Well this probably happens only to a dated gentoo installation where old conf files get orphaned. I was about to set some kernel module autoloading parameters, and was a bit confused seeing this:

$ ls -lad /etc/mod*
-rw-r--r-- 1 root root 3587 May  2  2008 /etc/modprobe.conf
drwxr-xr-x 2 root root  208 Mar 14 19:50 /etc/modprobe.d/
-rw-r--r-- 1 root root 2955 Dec  6  2007 /etc/modules.conf
drwxr-xr-x 2 root root   72 Jun  5  2008 /etc/modules.d/
$

The .conf files refer to two scripts, modules-update and update-modules, and the former doesn’t even exist. A man of the latter, however, clarifies everything. Here’s an excerpt from UPDATE-MODULES(8)

DESCRIPTION
       update-modules is a simple tool to manage the module config files found
       in the /etc/ directory.

       The old Linux module utilities use a single file for all their configu-
       ration.  This makes it difficult for packages to dynamically add infor-
       mation about their own modules.

       update-modules makes the dynamic addition of information easier by gen-
       erating  the  single  configuration file from the many files located in
       /etc/modules.d/.  All files in that directory are assembled together to
       form /etc/modules.conf.

       Newer Linux module utilities include support automatically for a direc-
       tory of configuration files in /etc/modprobe.d/.  However, to  maintain
       backwards  compatibility with packages that do not yet support this, we
       still need to assemble the contents of  /etc/modules.d/  and  /etc/mod-
       probe.d/  and produce the corresponding /etc/modules.conf and /etc/mod-
       probe.conf.

       Also, when  requested,  it  is  also  possible  to  generate  /etc/mod-
       ules.devfs.