[PATCH] cdc-ether: clean packet filter upon probe

[Oliver Neukum <oneukum@suse.de>]

There are devices that don't do reset all the way. So the packet filter should
be set to a sane initial value. Failure to do so leads to intermittent failures
of DHCP on some systems under some conditions.

Signed-off-by: Oliver Neukum <oneukum@suse.de>
---
 drivers/net/usb/cdc_ether.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/drivers/net/usb/cdc_ether.c b/drivers/net/usb/cdc_ether.c
index 9ea4bfe..ef8f8f8 100644
--- a/drivers/net/usb/cdc_ether.c
+++ b/drivers/net/usb/cdc_ether.c
@@ -341,6 +341,22 @@ next_desc:
 		usb_driver_release_interface(driver, info->data);
 		return -ENODEV;
 	}
+
+	/* Some devices don't initialise properly. In particular
+	 * the packet filter is not reset. There are devices that
+	 * don't do reset all the way. So the packet filter should
+	 * be set to a sane initial value.
+	 */
+	usb_control_msg(dev->udev,
+			usb_sndctrlpipe(dev->udev, 0),
+			USB_CDC_SET_ETHERNET_PACKET_FILTER,
+			USB_TYPE_CLASS | USB_RECIP_INTERFACE,
+			USB_CDC_PACKET_TYPE_ALL_MULTICAST | USB_CDC_PACKET_TYPE_DIRECTED | USB_CDC_PACKET_TYPE_BROADCAST,
+			intf->cur_altsetting->desc.bInterfaceNumber,
+			NULL,
+			0,
+			1000 /* out of thin air */
+		);
 	return 0;
 
 bad_desc:
-- 
1.8.4.5