used by Debian for building some modules, e.g. nvidia

You need it, if for your kernel no nvidia driver is available or does
not build

Most simple situation (just rebuild):

	sudo dpkg-reconfigure nvidia-kernel-dkms

Sources and Modules can be found below:

	/var/lib/dkms/nvidia-current/319.82

to build it:

	dkms build -m nvidia-current -v 319.82 
	dkms install -m nvidia-current -v 319.82 

remove following files:

	/lib/modules/3.14-0.bpo.2-amd64/updates/dkms/nvidia-current.ko
	/var/lib/dkms/nvidia-current/319.82/3.14-0.bpo.2-amd64/x86_64/