-----Message d'origine-----
De : Claudiu Manoil [mailto:claudiu.manoil@freescale.com] 
Envoyé : mercredi 30 janvier 2013 16:56
À : voncken
Cc : netdev@vger.kernel.org
Objet : Re: Gianfar : Drop a long frame

On 1/30/2013 3:43 PM, voncken wrote:

	Hi Claudiu,

	I have a problem with the gianfar driver.

	My test conditions are:
		- Disable rxvlan hardware acceleration (ethtool -K ethx

rxvlan off)

		- Receive frame contains a VLAN tag and with a frame len set

to the 

MTU (1500 bytes).

	In this condition, when I received a long frame the bdp->length is 
set to 1538 bytes.
	I guess it is composed of:
		1500 bytes: L3 data bytes
		 + 14 bytes:  Ethernet header
		 + 4 bytes:  Vlan Tag header
		 + 8 bytes: FCB structure size GMAC_FCB_LEN
		 + 8 bytes: eTSEC padding
		 + 4 bytes: Frames CRC (FCS)

	The Maximum frame len is set to 1536 because the function 
gfar_change_mtu does not integrate the FCS in the computed frame size.
	In this condition this frame is dropped with the test line 2792 
function gfar_clean_rx_ring
		if (unlikely(!(bdp->status & RXBD_ERR) &&
				bdp->length > priv->rx_buffer_size))
			bdp->status = RXBD_LARGE;
	
	How I can receive this frame correctly?
	
	Best regards

Cedric Voncken | R&d Engineer

Hi Cedric Voncken,
Is the 802.1Q support activated on the receiving host? (see
CONFIG_VLAN_8021Q)

Hi Claudiu, 

YEs the CONFIG_VLAN_8021Q is enable on the receiving host, that work
correctly if RXVLAN is set to on (ethtool -K ethx rxvlan off)
I try with the linux kernel 3.3.8.

Regards.