Hacking Linux Kernel

While recompiling a custom kernel depmod -a creates a "Makefile"-like dependency file, based on the symbols it finds in the set of modules mentioned on the command line or from the directories specified in the configuration file. This dependency file is later used by modprobe to automatically load the correct module or stack of modules.

If you are curious about which drivers are running and their purpose. Here is how to get started
Modules loaded automatically at boot time can be found under /lib/modules/KERNELNAME

The list of running modules can be found using
lsmod
$ less /proc/modules

More information about the modules can be found via
/sbin/modinfo video

free -m