cdc_subset: deal with a device that needs reset for timeout

This device needs to be reset to recover from a timeout.
Unfortunately this can be handled only at the level of
the subdrivers.

Signed-off-by: Oliver Neukum <oneukum@suse.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 36 insertions, 2 deletions

diff --git a/drivers/net/usb/cdc_subset.c b/drivers/net/usb/cdc_subset.c
index 91f0919fe278..3ef411efd86e 100644
--- a/drivers/net/usb/cdc_subset.c
+++ b/drivers/net/usb/cdc_subset.c
@@ -85,9 +85,34 @@ static int always_connected (struct usbnet *dev)
  *
  *-------------------------------------------------------------------------*/
 
+static void m5632_recover(struct usbnet *dev)
+{
+        struct usb_device       *udev = dev->udev;
+        struct usb_interface    *intf = dev->intf;
+        int r;
+
+        r = usb_lock_device_for_reset(udev, intf);
+        if (r < 0)
+                return;
+
+        usb_reset_device(udev);
+        usb_unlock_device(udev);
+}
+
+static int dummy_prereset(struct usb_interface *intf)
+{
+        return 0;
+}
+
+static int dummy_postreset(struct usb_interface *intf)
+{
+        return 0;
+}
+
 static const struct driver_info ali_m5632_info = {
         .description =  "ALi M5632",
         .flags       = FLAG_POINTTOPOINT,
+        .recover     = m5632_recover,
 };
 
 #endif
@@ -332,6 +357,8 @@ static struct usb_driver cdc_subset_driver = {
         .probe =        usbnet_probe,
         .suspend =      usbnet_suspend,
         .resume =       usbnet_resume,
+        .pre_reset =    dummy_prereset,
+        .post_reset =   dummy_postreset,
         .disconnect =   usbnet_disconnect,
         .id_table =     products,
         .disable_hub_initiated_lpm = 1,
diff --git a/drivers/net/usb/usbnet.c b/drivers/net/usb/usbnet.c
index f9e96c427558..5173821a9575 100644
--- a/drivers/net/usb/usbnet.c
+++ b/drivers/net/usb/usbnet.c
@@ -1218,8 +1218,12 @@ void usbnet_tx_timeout (struct net_device *net)
 
         unlink_urbs (dev, &dev->txq);
         tasklet_schedule (&dev->bh);
-
-        // FIXME: device recovery -- reset?
+        /* this needs to be handled individually because the generic layer
+         * doesn't know what is sufficient and could not restore private
+         * information if a remedy of an unconditional reset were used.
+         */
+        if (dev->driver_info->recover)
+                (dev->driver_info->recover)(dev);
 }
 EXPORT_SYMBOL_GPL(usbnet_tx_timeout);
 
diff --git a/include/linux/usb/usbnet.h b/include/linux/usb/usbnet.h
index 0662e98fef72..26088feb6608 100644
--- a/include/linux/usb/usbnet.h
+++ b/include/linux/usb/usbnet.h
@@ -148,6 +148,9 @@ struct driver_info {
         struct sk_buff  *(*tx_fixup)(struct usbnet *dev,
                                 struct sk_buff *skb, gfp_t flags);
 
+        /* recover from timeout */
+        void    (*recover)(struct usbnet *dev);
+
         /* early initialization code, can sleep. This is for minidrivers
          * having 'subminidrivers' that need to do extra initialization
          * right after minidriver have initialized hardware. */