USB: Force unbinding of drivers lacking reset_resume or other methods
This patch (as1024) takes care of a FIXME issue: Drivers that don't
have the necessary suspend, resume, reset_resume, pre_reset, or
post_reset methods will be unbound and their interface reprobed when
one of the unsupported events occurs.
This is made slightly more difficult by the fact that bind operations
won't work during a system sleep transition. So instead the code has
to defer the operation until the transition ends.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/usb/core/driver.c b/drivers/usb/core/driver.c
index 8da1a56..ddb54e1 100644
--- a/drivers/usb/core/driver.c
+++ b/drivers/usb/core/driver.c
@@ -201,6 +201,7 @@
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 @@
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 @@
}
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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 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 @@
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. */