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 6c0bb38c4089cf309eecf6776a13a27ff5df6736..8d4d46f3fd161e0545f64c2c682b40671e47c3a9 100644 (file)
--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -1828,6 +1828,13 @@ 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) },