4 files changed, 140 insertions, 21 deletions

diff --git a/drivers/usb/core/driver.c b/drivers/usb/core/driver.c
index 8da1a56659be..ddb54e14a5c5 100644
--- a/drivers/usb/core/driver.c
+++ b/drivers/usb/core/driver.c
@@ -201,6 +201,7 @@ static int usb_probe_interface(struct device *dev)
 
         intf = to_usb_interface(dev);
         udev = interface_to_usbdev(intf);
+        intf->needs_binding = 0;
 
         if (udev->authorized == 0) {
                 dev_err(&intf->dev, "Device is not authorized for usage\n");
@@ -311,6 +312,7 @@ int usb_driver_claim_interface(struct usb_driver *driver,
 
         dev->driver = &driver->drvwrap.driver;
         usb_set_intfdata(iface, priv);
+        iface->needs_binding = 0;
 
         usb_pm_lock(udev);
         iface->condition = USB_INTERFACE_BOUND;
@@ -772,6 +774,104 @@ void usb_deregister(struct usb_driver *driver)
 }
 EXPORT_SYMBOL_GPL(usb_deregister);
 
+
+/* Forced unbinding of a USB interface driver, either because
+ * it doesn't support pre_reset/post_reset/reset_resume or
+ * because it doesn't support suspend/resume.
+ *
+ * The caller must hold @intf's device's lock, but not its pm_mutex
+ * and not @intf->dev.sem.
+ */
+void usb_forced_unbind_intf(struct usb_interface *intf)
+{
+        struct usb_driver *driver = to_usb_driver(intf->dev.driver);
+
+        dev_dbg(&intf->dev, "forced unbind\n");
+        usb_driver_release_interface(driver, intf);
+
+        /* Mark the interface for later rebinding */
+        intf->needs_binding = 1;
+}
+
+/* Delayed forced unbinding of a USB interface driver and scan
+ * for rebinding.
+ *
+ * The caller must hold @intf's device's lock, but not its pm_mutex
+ * and not @intf->dev.sem.
+ *
+ * FIXME: The caller must block system sleep transitions.
+ */
+void usb_rebind_intf(struct usb_interface *intf)
+{
+        int rc;
+
+        /* Delayed unbind of an existing driver */
+        if (intf->dev.driver) {
+                struct usb_driver *driver =
+                                to_usb_driver(intf->dev.driver);
+
+                dev_dbg(&intf->dev, "forced unbind\n");
+                usb_driver_release_interface(driver, intf);
+        }
+
+        /* Try to rebind the interface */
+        intf->needs_binding = 0;
+        rc = device_attach(&intf->dev);
+        if (rc < 0)
+                dev_warn(&intf->dev, "rebind failed: %d\n", rc);
+}
+
+#define DO_UNBIND       0
+#define DO_REBIND       1
+
+/* Unbind drivers for @udev's interfaces that don't support suspend/resume,
+ * or rebind interfaces that have been unbound, according to @action.
+ *
+ * The caller must hold @udev's device lock.
+ * FIXME: For rebinds, the caller must block system sleep transitions.
+ */
+static void do_unbind_rebind(struct usb_device *udev, int action)
+{
+        struct usb_host_config  *config;
+        int                     i;
+        struct usb_interface    *intf;
+        struct usb_driver       *drv;
+
+        config = udev->actconfig;
+        if (config) {
+                for (i = 0; i < config->desc.bNumInterfaces; ++i) {
+                        intf = config->interface[i];
+                        switch (action) {
+                        case DO_UNBIND:
+                                if (intf->dev.driver) {
+                                        drv = to_usb_driver(intf->dev.driver);
+                                        if (!drv->suspend || !drv->resume)
+                                                usb_forced_unbind_intf(intf);
+                                }
+                                break;
+                        case DO_REBIND:
+                                if (intf->needs_binding) {
+
+        /* FIXME: The next line is needed because we are going to probe
+         * the interface, but as far as the PM core is concerned the
+         * interface is still suspended.  The problem wouldn't exist
+         * if we could rebind the interface during the interface's own
+         * resume() call, but at the time the usb_device isn't locked!
+         *
+         * The real solution will be to carry this out during the device's
+         * complete() callback.  Until that is implemented, we have to
+         * use this hack.
+         */
+//                                      intf->dev.power.sleeping = 0;
+
+                                        usb_rebind_intf(intf);
+                                }
+                                break;
+                        }
+                }
+        }
+}
+
 #ifdef CONFIG_PM
 
 /* Caller has locked udev's pm_mutex */
@@ -841,7 +941,7 @@ static int usb_suspend_interface(struct usb_interface *intf, pm_message_t msg)
                 goto done;
         driver = to_usb_driver(intf->dev.driver);
 
-        if (driver->suspend && driver->resume) {
+        if (driver->suspend) {
                 status = driver->suspend(intf, msg);
                 if (status == 0)
                         mark_quiesced(intf);
@@ -849,12 +949,10 @@ static int usb_suspend_interface(struct usb_interface *intf, pm_message_t msg)
                         dev_err(&intf->dev, "%s error %d\n",
                                         "suspend", status);
         } else {
-                /*
-                 * FIXME else if there's no suspend method, disconnect...
-                 * Not possible if auto_pm is set...
-                 */
-                dev_warn(&intf->dev, "no suspend for driver %s?\n",
-                                driver->name);
+                /* Later we will unbind the driver and reprobe */
+                intf->needs_binding = 1;
+                dev_warn(&intf->dev, "no %s for driver %s?\n",
+                                "suspend", driver->name);
                 mark_quiesced(intf);
         }
 
@@ -878,10 +976,12 @@ static int usb_resume_interface(struct usb_interface *intf, int reset_resume)
                 goto done;
 
         /* Can't resume it if it doesn't have a driver. */
-        if (intf->condition == USB_INTERFACE_UNBOUND) {
-                status = -ENOTCONN;
+        if (intf->condition == USB_INTERFACE_UNBOUND)
+                goto done;
+
+        /* Don't resume if the interface is marked for rebinding */
+        if (intf->needs_binding)
                 goto done;
-        }
         driver = to_usb_driver(intf->dev.driver);
 
         if (reset_resume) {
@@ -891,7 +991,7 @@ static int usb_resume_interface(struct usb_interface *intf, int reset_resume)
                                 dev_err(&intf->dev, "%s error %d\n",
                                                 "reset_resume", status);
                 } else {
-                        /* status = -EOPNOTSUPP; */
+                        intf->needs_binding = 1;
                         dev_warn(&intf->dev, "no %s for driver %s?\n",
                                         "reset_resume", driver->name);
                 }
@@ -902,7 +1002,7 @@ static int usb_resume_interface(struct usb_interface *intf, int reset_resume)
                                 dev_err(&intf->dev, "%s error %d\n",
                                                 "resume", status);
                 } else {
-                        /* status = -EOPNOTSUPP; */
+                        intf->needs_binding = 1;
                         dev_warn(&intf->dev, "no %s for driver %s?\n",
                                         "resume", driver->name);
                 }
@@ -910,11 +1010,10 @@ static int usb_resume_interface(struct usb_interface *intf, int reset_resume)
 
 done:
         dev_vdbg(&intf->dev, "%s: status %d\n", __func__, status);
-        if (status == 0)
+        if (status == 0 && intf->condition == USB_INTERFACE_BOUND)
                 mark_active(intf);
 
-        /* FIXME: Unbind the driver and reprobe if the resume failed
-         * (not possible if auto_pm is set) */
+        /* Later we will unbind the driver and/or reprobe, if necessary */
         return status;
 }
 
@@ -1470,6 +1569,7 @@ int usb_external_suspend_device(struct usb_device *udev, pm_message_t msg)
 {
         int     status;
 
+        do_unbind_rebind(udev, DO_UNBIND);
         usb_pm_lock(udev);
         udev->auto_pm = 0;
         status = usb_suspend_both(udev, msg);
@@ -1497,6 +1597,7 @@ int usb_external_resume_device(struct usb_device *udev)
         status = usb_resume_both(udev);
         udev->last_busy = jiffies;
         usb_pm_unlock(udev);
+        do_unbind_rebind(udev, DO_REBIND);
 
         /* Now that the device is awake, we can start trying to autosuspend
          * it again. */
diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index bb3ecc4c08f2..f1efabbc1ca2 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -3367,6 +3367,11 @@ re_enumerate:
  * this from a driver probe() routine after downloading new firmware.
  * For calls that might not occur during probe(), drivers should lock
  * the device using usb_lock_device_for_reset().
+ *
+ * If an interface is currently being probed or disconnected, we assume
+ * its driver knows how to handle resets.  For all other interfaces,
+ * if the driver doesn't have pre_reset and post_reset methods then
+ * we attempt to unbind it and rebind afterward.
  */
 int usb_reset_device(struct usb_device *udev)
 {
@@ -3388,12 +3393,17 @@ int usb_reset_device(struct usb_device *udev)
                 for (i = 0; i < config->desc.bNumInterfaces; ++i) {
                         struct usb_interface *cintf = config->interface[i];
                         struct usb_driver *drv;
+                        int unbind = 0;
 
                         if (cintf->dev.driver) {
                                 drv = to_usb_driver(cintf->dev.driver);
-                                if (drv->pre_reset)
-                                        (drv->pre_reset)(cintf);
-        /* FIXME: Unbind if pre_reset returns an error or isn't defined */
+                                if (drv->pre_reset && drv->post_reset)
+                                        unbind = (drv->pre_reset)(cintf);
+                                else if (cintf->condition ==
+                                                USB_INTERFACE_BOUND)
+                                        unbind = 1;
+                                if (unbind)
+                                        usb_forced_unbind_intf(cintf);
                         }
                 }
         }
@@ -3404,13 +3414,18 @@ int usb_reset_device(struct usb_device *udev)
                 for (i = config->desc.bNumInterfaces - 1; i >= 0; --i) {
                         struct usb_interface *cintf = config->interface[i];
                         struct usb_driver *drv;
+                        int rebind = cintf->needs_binding;
 
-                        if (cintf->dev.driver) {
+                        if (!rebind && cintf->dev.driver) {
                                 drv = to_usb_driver(cintf->dev.driver);
                                 if (drv->post_reset)
-                                        (drv->post_reset)(cintf);
-        /* FIXME: Unbind if post_reset returns an error or isn't defined */
+                                        rebind = (drv->post_reset)(cintf);
+                                else if (cintf->condition ==
+                                                USB_INTERFACE_BOUND)
+                                        rebind = 1;
                         }
+                        if (rebind)
+                                usb_rebind_intf(cintf);
                 }
         }
 
diff --git a/drivers/usb/core/usb.h b/drivers/usb/core/usb.h
index 1a8bc21c335e..d3eb0a29bca1 100644
--- a/drivers/usb/core/usb.h
+++ b/drivers/usb/core/usb.h
@@ -29,6 +29,8 @@ extern int usb_choose_configuration(struct usb_device *udev);
 extern void usb_kick_khubd(struct usb_device *dev);
 extern int usb_match_device(struct usb_device *dev,
                             const struct usb_device_id *id);
+extern void usb_forced_unbind_intf(struct usb_interface *intf);
+extern void usb_rebind_intf(struct usb_interface *intf);
 
 extern int  usb_hub_init(void);
 extern void usb_hub_cleanup(void);
diff --git a/include/linux/usb.h b/include/linux/usb.h
index 3cc8db5254d1..5811c5da69f9 100644
--- a/include/linux/usb.h
+++ b/include/linux/usb.h
@@ -160,6 +160,7 @@ struct usb_interface {
         unsigned is_active:1;           /* the interface is not suspended */
         unsigned sysfs_files_created:1; /* the sysfs attributes exist */
         unsigned needs_remote_wakeup:1; /* driver requires remote wakeup */
+        unsigned needs_binding:1;       /* needs delayed unbind/rebind */
 
         struct device dev;              /* interface specific device info */
         struct device *usb_dev;