pci_get_subsys — begin or continue searching for a PCI device by vendor/subvendor/device/subdevice id
| struct pci_dev * pci_get_subsys ( | unsigned int vendor, | 
| unsigned int device, | |
| unsigned int ss_vendor, | |
| unsigned int ss_device, | |
| struct pci_dev * from ); | 
vendor
     PCI vendor id to match, or PCI_ANY_ID to match all vendor ids
    
device
     PCI device id to match, or PCI_ANY_ID to match all device ids
    
ss_vendor
     PCI subsystem vendor id to match, or PCI_ANY_ID to match all vendor ids
    
ss_device
     PCI subsystem device id to match, or PCI_ANY_ID to match all device ids
    
from
     Previous PCI device found in search, or NULL for new search.
    
   Iterates through the list of known PCI devices.  If a PCI device is found
   with a matching vendor, device, ss_vendor and ss_device, a pointer to its
   device structure is returned, and the reference count to the device is
   incremented.  Otherwise, NULL is returned.  A new search is initiated by
   passing NULL as the from argument.  Otherwise if from is not NULL,
   searches continue from next device on the global list.
   The reference count for from is always decremented if it is not NULL.