[root@ironman ~]# ls /sys/bus/pci/devices/0000\:00\:19.0/
broken_parity_status	  d3cold_allowed  enable	 label		msi_bus    power   reset      resource2		uevent
class			  device	  firmware_node  local_cpulist	msi_irqs   ptp	   resource   subsystem		vendor
config			  dma_mask_bits   index		 local_cpus	net	   remove  resource0  subsystem_device
consistent_dma_mask_bits  driver	  irq		 modalias	numa_node  rescan  resource1  subsystem_vendor

[root@ironman ~]# cat /sys/bus/pci/devices/0000\:00\:19.0/index
1

[root@ironman ~]# ls /sys/bus/pci/devices/0000\:02\:00.0/
broken_parity_status	  d3cold_allowed  enable	 label		msi_bus    power   reset      resource3		uevent
class			  device	  firmware_node  local_cpulist	msi_irqs   ptp	   resource   subsystem		vendor
config			  dma_mask_bits   index		 local_cpus	net	   remove  resource0  subsystem_device
consistent_dma_mask_bits  driver	  irq		 modalias	numa_node  rescan  resource2  subsystem_vendor

[root@ironman ~]# cat /sys/bus/pci/devices/0000\:02\:00.0/index 
1