USB: handle more rndis_host oddities

Workaround another device firmware bug, wherein CDC descriptors get
placed in a wrong place never previously observed in the wild.

Fix a bug where a seeming RNDIS device returns a bogus response during
device initialization.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 16 insertions, 0 deletions

diff --git a/drivers/net/usb/cdc_ether.c b/drivers/net/usb/cdc_ether.c
index 5a21f06bf8a5..675ac99a79c6 100644
--- a/drivers/net/usb/cdc_ether.c
+++ b/drivers/net/usb/cdc_ether.c
@@ -91,6 +91,22 @@ int usbnet_generic_cdc_bind(struct usbnet *dev, struct usb_interface *intf)
                                 "CDC descriptors on config\n");
         }
 
+        /* Maybe CDC descriptors are after the endpoint?  This bug has
+         * been seen on some 2Wire Inc RNDIS-ish products.
+         */
+        if (len == 0) {
+                struct usb_host_endpoint        *hep;
+
+                hep = intf->cur_altsetting->endpoint;
+                if (hep) {
+                        buf = hep->extra;
+                        len = hep->extralen;
+                }
+                if (len)
+                        dev_dbg(&intf->dev,
+                                "CDC descriptors on endpoint\n");
+        }
+
         /* this assumes that if there's a non-RNDIS vendor variant
          * of cdc-acm, it'll fail RNDIS requests cleanly.
          */