diff --git a/drivers/usb/core/message.c b/drivers/usb/core/message.c
index 5ab5c1a81462b621d335b2f3a9ef40268dc73a99..3a47077461578f2af47af8d551353c2c7cb12f0e 100644
--- a/drivers/usb/core/message.c
+++ b/drivers/usb/core/message.c
@@ -1859,7 +1859,12 @@ int usb_set_configuration(struct usb_device *dev, int configuration)
 		intf->dev.bus = &usb_bus_type;
 		intf->dev.type = &usb_if_device_type;
 		intf->dev.groups = usb_interface_groups;
+		/*
+		 * Please refer to usb_alloc_dev() to see why we set
+		 * dma_mask and dma_pfn_offset.
+		 */
 		intf->dev.dma_mask = dev->dev.dma_mask;
+		intf->dev.dma_pfn_offset = dev->dev.dma_pfn_offset;
 		INIT_WORK(&intf->reset_ws, __usb_queue_reset_device);
 		intf->minor = -1;
 		device_initialize(&intf->dev);
diff --git a/drivers/usb/core/usb.c b/drivers/usb/core/usb.c
index 5e80697ef952d9ccc39cd786236a2e208ad084a7..5921514610179f04232e11da85746344ff3ee3e0 100644
--- a/drivers/usb/core/usb.c
+++ b/drivers/usb/core/usb.c
@@ -440,7 +440,18 @@ struct usb_device *usb_alloc_dev(struct usb_device *parent,
 	dev->dev.bus = &usb_bus_type;
 	dev->dev.type = &usb_device_type;
 	dev->dev.groups = usb_device_groups;
+	/*
+	 * Fake a dma_mask/offset for the USB device:
+	 * We cannot really use the dma-mapping API (dma_alloc_* and
+	 * dma_map_*) for USB devices but instead need to use
+	 * usb_alloc_coherent and pass data in 'urb's, but some subsystems
+	 * manually look into the mask/offset pair to determine whether
+	 * they need bounce buffers.
+	 * Note: calling dma_set_mask() on a USB device would set the
+	 * mask for the entire HCD, so don't do that.
+	 */
 	dev->dev.dma_mask = bus->controller->dma_mask;
+	dev->dev.dma_pfn_offset = bus->controller->dma_pfn_offset;
 	set_dev_node(&dev->dev, dev_to_node(bus->controller));
 	dev->state = USB_STATE_ATTACHED;
 	dev->lpm_disable_count = 1;