[PATCH] USB: otg hub support is optional

USB OTG devices are not required to support external hubs.  This adds a
configuration option to disable that support.

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

1 files changed, 7 insertions, 0 deletions

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 3c76f7e17c0c..0c87f73f2933 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -836,6 +836,13 @@ static int hub_probe(struct usb_interface *intf, const struct usb_device_id *id)
         desc = intf->cur_altsetting;
         hdev = interface_to_usbdev(intf);
 
+#ifdef  CONFIG_USB_OTG_BLACKLIST_HUB
+        if (hdev->parent) {
+                dev_warn(&intf->dev, "ignoring external hub\n");
+                return -ENODEV;
+        }
+#endif
+
         /* Some hubs have a subclass of 1, which AFAICT according to the */
         /*  specs is not defined, but it works */
         if ((desc->desc.bInterfaceSubClass != 0) &&