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 423a339e53bc731f1fb24e2652863975ae890ca6..8ab0195f8d32caf02e1b99a2b00adf82e8394262 100644 (file)
--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -1893,6 +1893,13 @@ 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) },