> ls -R /sys/bus
/sys/bus:
pci  pci_express  pcmcia  scsi  usb
/sys/bus/pci:
devices  drivers
/sys/bus/pci/devices:
0000:00:00.0  0000:00:1a.7  0000:00:1c.3  0000:00:1d.7  0000:00:1f.3
0000:00:01.0  0000:00:1b.0  0000:00:1c.4  0000:00:1e.0  0000:01:00.0
/sys/bus/pci/drivers:
agpgart-intel  ata_piix  ehci_hcd  ohci_hcd  uhci_hcd  ahci  e1000  HDA Intel
...