Re: [dpdk-dev] [PATCH v1] net: i40e: add VLAN tag size to RXMAX

["Wu, Jingjing" <jingjing.wu@intel.com>]

Hi, Nikita

dev_conf.rxmode.max_rx_pkt_len is different with MTU concept.
The max_rx_pkt_len indicates the maximum packet length it can receive, it should be larger than MTU.
 
There is another patch which is enabling set_mtu ops.
http://dpdk.org/dev/patchwork/patch/12218/
You can definitely help to review and comment it.

Thanks
Jingjing

> -----Original Message-----
> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Nikita Kozlov
> Sent: Friday, May 06, 2016 11:51 PM
> To: Zhang, Helin
> Cc: dev@dpdk.org
> Subject: Re: [dpdk-dev] [PATCH v1] net: i40e: add VLAN tag size to RXMAX
> 
> Hello,
> 
> On 09/ 1/15 07:34 AM, Zhang, Helin wrote:
> >> -----Original Message-----
> >> From: Vlad Zolotarov [mailto:vladz@cloudius-systems.com]
> >> Sent: Monday, August 31, 2015 2:42 PM
> >> To: dev@dpdk.org
> >> Cc: Zhang, Helin; Ananyev, Konstantin; avi@cloudius-systems.com; Vlad
> >> Zolotarov
> >> Subject: [dpdk-dev] [PATCH v1] net: i40e: add VLAN tag size to RXMAX
> >>
> >> HW requires it regardless the presence of the VLAN tag in the received
> frame.
> >> Otherwise Rx frames are being filtered out on the MTU-4 boundary.
> > Maximum packet length could have different meanings from MTU. I agree
> > with you to have it be regardless of vlan tag length.
> >
> >> Signed-off-by: Vlad Zolotarov <vladz@cloudius-systems.com>
> >> ---
> >>  drivers/net/i40e/i40e_rxtx.c | 2 +-
> >>  1 file changed, 1 insertion(+), 1 deletion(-)
> >>
> >> diff --git a/drivers/net/i40e/i40e_rxtx.c
> >> b/drivers/net/i40e/i40e_rxtx.c index
> >> eae4ab0..22aaeb1 100644
> >> --- a/drivers/net/i40e/i40e_rxtx.c
> >> +++ b/drivers/net/i40e/i40e_rxtx.c
> >> @@ -3156,7 +3156,7 @@ i40e_rx_queue_init(struct i40e_rx_queue *rxq)
> >>  		rx_ctx.hsplit_0 = I40E_HEADER_SPLIT_ALL;
> >>  	else
> >>  		rx_ctx.hsplit_0 = I40E_HEADER_SPLIT_NONE;
> >> -	rx_ctx.rxmax = rxq->max_pkt_len;
> >> +	rx_ctx.rxmax = rxq->max_pkt_len + I40E_VLAN_TAG_SIZE;
> > It needs to take into account the double vlan case, and also VF case.
> > It seems it needs more code changes. Thank you for the contribution!
> I was wondering if this "bug" haven't been forgotten ? Even if it his not
> patched yet maybe it is worth an entry in the documentation ?
> >
> > Regards,
> > Helin
> >
> >>  	rx_ctx.tphrdesc_ena = 1;
> >>  	rx_ctx.tphwdesc_ena = 1;
> >>  	rx_ctx.tphdata_ena = 1;
> >> --
> >> 2.1.0