summaryrefslogtreecommitdiff
path: root/drivers/usb/core/driver.c
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/usb/core/driver.c')
-rw-r--r--drivers/usb/core/driver.c50
1 files changed, 34 insertions, 16 deletions
diff --git a/drivers/usb/core/driver.c b/drivers/usb/core/driver.c
index c976ea9f9582..98b7449c11f3 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;
@@ -905,26 +930,19 @@ static int usb_uevent(struct device *dev, struct kobj_uevent_env *env)
return 0;
}
-static bool is_dev_usb_generic_driver(struct device *dev)
-{
- struct usb_device_driver *udd = dev->driver ?
- to_usb_device_driver(dev->driver) : NULL;
-
- return udd == &usb_generic_driver;
-}
-
static int __usb_bus_reprobe_drivers(struct device *dev, void *data)
{
struct usb_device_driver *new_udriver = data;
struct usb_device *udev;
int ret;
- if (!is_dev_usb_generic_driver(dev))
+ /* 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))
+ (!new_udriver->match || new_udriver->match(udev) == 0))
return 0;
ret = device_reprobe(dev);