NIC features in *nix

[Haden]

I can't seem to find how extra NIC features are implemented (if at all) in *nix drivers.
For example QoS, is it card dependant, always software or transparent and kicks in if NIC has support?

 

[Haden]

bump

I've took a look into ns83820.c, Linux driver for SMC9452TX, while there seems to be code for VLAN support I find nothing about QoS (nothing in other drivers either).