interesting thing about lspci ?

[Onkar <onkar.n.m@xxxxxxxxx>]

I am foxed with the lspci output 

       " lspci is a utility for displaying information about all PCI buses in the system and all devices connected to them. "

that means all the devices - devices for which drivers are available and devices for which kernel has to offer no drivers - 
if there are no dirvers how is Linux able to detect the device in the first place ?????


Thanks & regards,
Onkar