PCI dynids - documentation fixes, id_table NULL check

Documentation/pci.txt

@@ -45,8 +45,6 @@ contains:
 	id_table	Pointer to table of device ID's the driver is
 			interested in.  Most drivers should export this
 			table using MODULE_DEVICE_TABLE(pci,...).
-			Set to NULL to call probe() function for every
-			PCI device known to the system.
 	probe		Pointer to a probing function which gets called (during
 			execution of pci_register_driver for already existing
 			devices or later if a new device gets inserted) for all
@@ -83,6 +81,28 @@ Each entry consists of:
 	class_mask	of the class are honored during the comparison.
 	driver_data	Data private to the driver.
 
+Most drivers don't need to use the driver_data field.  Best practice
+for use of driver_data is to use it as an index into a static list of
+equivalant device types, not to use it as a pointer.
+
+Have a table entry {PCI_ANY_ID, PCI_ANY_ID, PCI_ANY_ID, PCI_ANY_ID}
+to have probe() called for every PCI device known to the system.
+
+New PCI IDs may be added to a device driver at runtime by writing
+to the file /sys/bus/pci/drivers/{driver}/new_id.  When added, the
+driver will probe for all devices it can support.
+
+echo "vendor device subvendor subdevice class class_mask driver_data" > \
+ /sys/bus/pci/drivers/{driver}/new_id
+where all fields are passed in as hexadecimal values (no leading 0x).
+Users need pass only as many fields as necessary; vendor, device,
+subvendor, and subdevice fields default to PCI_ANY_ID (FFFFFFFF),
+class and classmask fields default to 0, and driver_data defaults to
+0UL.  Device drivers must call
+   pci_dynids_set_use_driver_data(pci_driver *, 1)
+in order for the driver_data field to get passed to the driver.
+Otherwise, only a 0 is passed in that field.
+
 When the driver exits, it just calls pci_unregister_driver() and the PCI layer
 automatically calls the remove hook for all devices handled by the driver.
 

drivers/pci/pci-driver.c

@@ -66,6 +66,8 @@ pci_device_probe_static(struct pci_driver *drv,
 	int error = -ENODEV;
 	const struct pci_device_id *id;
 
+	if (!drv->id_table)
+		return error;
 	id = pci_match_device(drv->id_table, pci_dev);
 	if (id)
 		error = drv->probe(pci_dev, id);

include/linux/pci.h

@@ -499,7 +499,7 @@ struct pci_dynids {
 struct pci_driver {
 	struct list_head node;
 	char *name;
-	const struct pci_device_id *id_table;	/* NULL if wants all devices */
+	const struct pci_device_id *id_table;	/* must be non-NULL for probe to be called */
 	int  (*probe)  (struct pci_dev *dev, const struct pci_device_id *id);	/* New device inserted */
 	void (*remove) (struct pci_dev *dev);	/* Device removed (NULL if not a hot-plug capable driver) */
 	int  (*save_state) (struct pci_dev *dev, u32 state);    /* Save Device Context */