In linux world. The driver u refer to can be a:
1. Module in linux kernel (where u can load it dynamically when u want to use it).
Commands related to it are:
lsmod -->display all the modules (drivers) ur kernel loaded and using/not using
insmod -->insert a module
rmmod --> removes a module
modprobe --> automatically detect and load the right module for your hardware if found.
OR
2. Source really compiled into the kernel.
ALSO
3. A binary (library file)
If vendor do provide this fella.
Sometimes it means that, even u have installed it, the system haven't load or identy the existence of the driver.
Try something like /sbin/ldconfig as root. Also make sure ur driver path is within the systems know library path. LD_LIBRARY....
else, u r just installing the drivers but not loading it to make that fella rock n rolling.