OSDev.org

Why, and how do I need to make a pci bus driver. I understand what the bus does and is, but dont inb and outb write to these devices automatically? And then there are memory mapped devices. So do I need to make a pci driver to do DMA writes to devices or something? Manually write a lot of data quickly?

A PCI bus driver would be responsible for enumerating the devices that are attached to it, and for altering their configuration (assigning resources etc.).

I see. I did a little googling too, By configuration does that include pci irq too?

Yes.