How does BIOS determine the type of device during PCI Express Bus Enumeration?

Question

During the PCI Express Bus enumeration, How does BIOS figure out the type of the device i.e. whether its a PCI or PCI express device?

score 1 · Answer 1 · answered Jan 02 '19 at 12:22

1

A PCI Express device must have a capability list and must have the PCI Express capability—capability ID 0x10.

answered Jan 02 '19 at 12:22

prl

I am aware of PCI Express capability register which has the type field indicating port type (root ports, switch downstream port, upstream switch port etc) but not sure if the same port type field indicates if its pci or pci express device ? – v123 May 29 '19 at 07:39

1 Answers1