net: usb: cdc_eem: fix mtu

vitkyrka · davem330 · commit 78fb72f7936c · 2012-04-01T23:32:35.000-04:00
Make CDC EEM recalculate the hard_mtu after adjusting the
hard_header_len.

Without this, usbnet adjusts the MTU down to 1494 bytes, and the host is
unable to receive standard 1500-byte frames from the device.

Tested with the Linux USB Ethernet gadget.

Cc: Oliver Neukum &lt;oliver@neukum.name&gt;
Signed-off-by: Rabin Vincent &lt;rabin@rab.in&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
diff --git a/drivers/net/usb/cdc_eem.c b/drivers/net/usb/cdc_eem.c
@@ -93,6 +93,7 @@ static int eem_bind(struct usbnet *dev, struct usb_interface *intf)
 	/* no jumbogram (16K) support for now */
 
 	dev->net->hard_header_len += EEM_HEAD + ETH_FCS_LEN;
+	dev->hard_mtu = dev->net->mtu + dev->net->hard_header_len;
 
 	return 0;
 }

Original file line number	Diff line number	Diff line change
`@@ -93,6 +93,7 @@ static int eem_bind(struct usbnet dev, struct usb_interface intf)`
`93`	`93`	`/* no jumbogram (16K) support for now */`
`94`	`94`
`95`	`95`	`dev->net->hard_header_len += EEM_HEAD + ETH_FCS_LEN;`
	`96`	`+ dev->hard_mtu = dev->net->mtu + dev->net->hard_header_len;`
`96`	`97`
`97`	`98`	`return 0;`
`98`	`99`	`}`