- req.bmRequestType = USB_TYPE_CLASS | USB_DIR_IN | USB_RECIP_INTERFACE;
- req.bNotificationType = USB_CDC_GET_MAX_DATAGRAM_SIZE;
- req.wValue = 0;
- req.wIndex = cpu_to_le16(iface_no);
- req.wLength = cpu_to_le16(2);
+ if (flags & USB_CDC_NCM_NCAP_MAX_DATAGRAM_SIZE) {
+ __le16 max_datagram_size;
+ u16 eth_max_sz = le16_to_cpu(ctx->ether_desc->wMaxSegmentSize);
+
+ req.bmRequestType = USB_TYPE_CLASS | USB_DIR_IN |
+ USB_RECIP_INTERFACE;
+ req.bNotificationType = USB_CDC_GET_MAX_DATAGRAM_SIZE;
+ req.wValue = 0;
+ req.wIndex = cpu_to_le16(iface_no);
+ req.wLength = cpu_to_le16(2);
+
+ err = cdc_ncm_do_request(ctx, &req, &max_datagram_size, 0, NULL,
+ 1000);
+ if (err) {
+ pr_debug("GET_MAX_DATAGRAM_SIZE failed, use size=%u\n",
+ CDC_NCM_MIN_DATAGRAM_SIZE);
+ } else {
+ ctx->max_datagram_size = le16_to_cpu(max_datagram_size);
+ /* Check Eth descriptor value */
+ if (eth_max_sz < CDC_NCM_MAX_DATAGRAM_SIZE) {
+ if (ctx->max_datagram_size > eth_max_sz)
+ ctx->max_datagram_size = eth_max_sz;
+ } else {
+ if (ctx->max_datagram_size >
+ CDC_NCM_MAX_DATAGRAM_SIZE)
+ ctx->max_datagram_size =
+ CDC_NCM_MAX_DATAGRAM_SIZE;
+ }