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path: root/drivers/usb/core/driver.c
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Diffstat (limited to 'drivers/usb/core/driver.c')
-rw-r--r--drivers/usb/core/driver.c70
1 files changed, 62 insertions, 8 deletions
diff --git a/drivers/usb/core/driver.c b/drivers/usb/core/driver.c
index f81606c6a35b..b351962279e4 100644
--- a/drivers/usb/core/driver.c
+++ b/drivers/usb/core/driver.c
@@ -269,8 +269,30 @@ static int usb_probe_device(struct device *dev)
if (error)
return error;
+ /* Probe the USB device with the driver in hand, but only
+ * defer to a generic driver in case the current USB
+ * device driver has an id_table or a match function; i.e.,
+ * when the device driver was explicitly matched against
+ * a device.
+ *
+ * If the device driver does not have either of these,
+ * then we assume that it can bind to any device and is
+ * not truly a more specialized/non-generic driver, so a
+ * return value of -ENODEV should not force the device
+ * to be handled by the generic USB driver, as there
+ * can still be another, more specialized, device driver.
+ *
+ * This accommodates the usbip driver.
+ *
+ * TODO: What if, in the future, there are multiple
+ * specialized USB device drivers for a particular device?
+ * In such cases, there is a need to try all matching
+ * specialised device drivers prior to setting the
+ * use_generic_driver bit.
+ */
error = udriver->probe(udev);
- if (error == -ENODEV && udriver != &usb_generic_driver) {
+ if (error == -ENODEV && udriver != &usb_generic_driver &&
+ (udriver->id_table || udriver->match)) {
udev->use_generic_driver = 1;
return -EPROBE_DEFER;
}
@@ -831,14 +853,17 @@ static int usb_device_match(struct device *dev, struct device_driver *drv)
udev = to_usb_device(dev);
udrv = to_usb_device_driver(drv);
- if (udrv->id_table &&
- usb_device_match_id(udev, udrv->id_table) != NULL) {
- return 1;
- }
+ if (udrv->id_table)
+ return usb_device_match_id(udev, udrv->id_table) != NULL;
if (udrv->match)
return udrv->match(udev);
- return 0;
+
+ /* If the device driver under consideration does not have a
+ * id_table or a match function, then let the driver's probe
+ * function decide.
+ */
+ return 1;
} else if (is_usb_interface(dev)) {
struct usb_interface *intf;
@@ -905,6 +930,28 @@ static int usb_uevent(struct device *dev, struct kobj_uevent_env *env)
return 0;
}
+static int __usb_bus_reprobe_drivers(struct device *dev, void *data)
+{
+ struct usb_device_driver *new_udriver = data;
+ struct usb_device *udev;
+ int ret;
+
+ /* Don't reprobe if current driver isn't usb_generic_driver */
+ if (dev->driver != &usb_generic_driver.drvwrap.driver)
+ return 0;
+
+ udev = to_usb_device(dev);
+ if (usb_device_match_id(udev, new_udriver->id_table) == NULL &&
+ (!new_udriver->match || new_udriver->match(udev) == 0))
+ return 0;
+
+ ret = device_reprobe(dev);
+ if (ret && ret != -EPROBE_DEFER)
+ dev_err(dev, "Failed to reprobe device (error %d)\n", ret);
+
+ return 0;
+}
+
/**
* usb_register_device_driver - register a USB device (not interface) driver
* @new_udriver: USB operations for the device driver
@@ -934,13 +981,20 @@ int usb_register_device_driver(struct usb_device_driver *new_udriver,
retval = driver_register(&new_udriver->drvwrap.driver);
- if (!retval)
+ if (!retval) {
pr_info("%s: registered new device driver %s\n",
usbcore_name, new_udriver->name);
- else
+ /*
+ * Check whether any device could be better served with
+ * this new driver
+ */
+ bus_for_each_dev(&usb_bus_type, NULL, new_udriver,
+ __usb_bus_reprobe_drivers);
+ } else {
printk(KERN_ERR "%s: error %d registering device "
" driver %s\n",
usbcore_name, retval, new_udriver->name);
+ }
return retval;
}