diff options
Diffstat (limited to 'drivers/usb/core/driver.c')
| -rw-r--r-- | drivers/usb/core/driver.c | 50 |
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); |