usb: cdc-acm: send ZLP for Telit 3G Intel based modems

commit 34aabf918717dd14e05051896aaecd3b16b53d95 upstream.

Telit 3G Intel based modems require zero packet to be sent if
out data size is equal to the endpoint max packet size.

Signed-off-by: Daniele Palmas <dnlplm@gmail.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c
index ed8c62b2d9d1ed582ac3d2bd1a98760ef39c2735..739f8960811ac89d6f960a184155f4e0c602101a 100644 (file)
--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -1865,6 +1865,13 @@ static const struct usb_device_id acm_ids[] = {
        .driver_info = IGNORE_DEVICE,
        },
 
+       { USB_DEVICE(0x1bc7, 0x0021), /* Telit 3G ACM only composition */
+       .driver_info = SEND_ZERO_PACKET,
+       },
+       { USB_DEVICE(0x1bc7, 0x0023), /* Telit 3G ACM + ECM composition */
+       .driver_info = SEND_ZERO_PACKET,
+       },
+
        /* control interfaces without any protocol set */
        { USB_INTERFACE_INFO(USB_CLASS_COMM, USB_CDC_SUBCLASS_ACM,
                USB_CDC_PROTO_NONE) },