From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Kirsher Subject: [net-next 02/15] fm10k: Correct MTU for jumbo frames Date: Mon, 23 Nov 2015 11:36:03 -0800 Message-ID: <1448307376-20063-3-git-send-email-jeffrey.t.kirsher@intel.com> References: <1448307376-20063-1-git-send-email-jeffrey.t.kirsher@intel.com> Cc: Jacob Keller , netdev@vger.kernel.org, nhorman@redhat.com, sassmann@redhat.com, jogreene@redhat.com, Matthew Vick , Jeff Kirsher To: davem@davemloft.net Return-path: Received: from mga01.intel.com ([192.55.52.88]:40449 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751699AbbKWTgV (ORCPT ); Mon, 23 Nov 2015 14:36:21 -0500 In-Reply-To: <1448307376-20063-1-git-send-email-jeffrey.t.kirsher@intel.com> Sender: netdev-owner@vger.kernel.org List-ID: From: Jacob Keller Based on hardware testing, the host interface supports up to 15368 bytes as the maximum frame size. To determine the correct MTU, we subtract 8 for the internal switch tag, 14 for the L2 header, and 4 for the appended FCS header, resulting in 15342 bytes of payload for our maximum MTU on jumbo frames. Signed-off-by: Matthew Vick Signed-off-by: Jacob Keller Acked-by: Bruce Allan Tested-by: Krishneil Singh Signed-off-by: Jeff Kirsher --- drivers/net/ethernet/intel/fm10k/fm10k.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/net/ethernet/intel/fm10k/fm10k.h b/drivers/net/ethernet/intel/fm10k/fm10k.h index 1444020..48809e5 100644 --- a/drivers/net/ethernet/intel/fm10k/fm10k.h +++ b/drivers/net/ethernet/intel/fm10k/fm10k.h @@ -33,7 +33,7 @@ #include "fm10k_pf.h" #include "fm10k_vf.h" -#define FM10K_MAX_JUMBO_FRAME_SIZE 15358 /* Maximum supported size 15K */ +#define FM10K_MAX_JUMBO_FRAME_SIZE 15342 /* Maximum supported size 15K */ #define MAX_QUEUES FM10K_MAX_QUEUES_PF -- 2.5.0