[dpdk-dev] [PATCH] net/e1000: fix max Rx packet size

[Alvin Zhang]

According to E1000_ETH_OVERHEAD definition, max_rx_pkt_len contains
one VLAN tag size. Therefor when config RLPML register, if dual VLAN
not enabled there is no need to add VLAN tag size to max_rx_pkt_len,
otherwise only one another VLAN tag size should be added to.

Fixes: e51abef39382 ("igb: fix max RX packet size and support dual VLAN")
Cc: sta...@dpdk.org

Signed-off-by: Alvin Zhang <alvinx.zh...@intel.com>
---
 drivers/net/e1000/igb_ethdev.c | 5 ++---
 drivers/net/e1000/igb_rxtx.c   | 9 ++++++---
 2 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/drivers/net/e1000/igb_ethdev.c b/drivers/net/e1000/igb_ethdev.c
index 2927cd7..7df7b0f 100644
--- a/drivers/net/e1000/igb_ethdev.c
+++ b/drivers/net/e1000/igb_ethdev.c
@@ -2688,8 +2688,7 @@ static int eth_igbvf_xstats_get_names(__rte_unused struct 
rte_eth_dev *dev,
        /* Update maximum packet length */
        if (dev->data->dev_conf.rxmode.offloads & DEV_RX_OFFLOAD_JUMBO_FRAME)
                E1000_WRITE_REG(hw, E1000_RLPML,
-                       dev->data->dev_conf.rxmode.max_rx_pkt_len +
-                                               VLAN_TAG_SIZE);
+                               dev->data->dev_conf.rxmode.max_rx_pkt_len);
 }
 
 static void
@@ -2708,7 +2707,7 @@ static int eth_igbvf_xstats_get_names(__rte_unused struct 
rte_eth_dev *dev,
        if (dev->data->dev_conf.rxmode.offloads & DEV_RX_OFFLOAD_JUMBO_FRAME)
                E1000_WRITE_REG(hw, E1000_RLPML,
                        dev->data->dev_conf.rxmode.max_rx_pkt_len +
-                                               2 * VLAN_TAG_SIZE);
+                                               VLAN_TAG_SIZE);
 }
 
 static int
diff --git a/drivers/net/e1000/igb_rxtx.c b/drivers/net/e1000/igb_rxtx.c
index 1500d2f..81f06f9 100644
--- a/drivers/net/e1000/igb_rxtx.c
+++ b/drivers/net/e1000/igb_rxtx.c
@@ -2343,15 +2343,18 @@ int eth_igb_rss_hash_conf_get(struct rte_eth_dev *dev,
         * Configure support of jumbo frames, if any.
         */
        if (dev->data->dev_conf.rxmode.offloads & DEV_RX_OFFLOAD_JUMBO_FRAME) {
+               uint32_t max_len = dev->data->dev_conf.rxmode.max_rx_pkt_len;
+
                rctl |= E1000_RCTL_LPE;
 
                /*
                 * Set maximum packet length by default, and might be updated
                 * together with enabling/disabling dual VLAN.
                 */
-               E1000_WRITE_REG(hw, E1000_RLPML,
-                       dev->data->dev_conf.rxmode.max_rx_pkt_len +
-                                               VLAN_TAG_SIZE);
+               if (rxmode->offloads & DEV_RX_OFFLOAD_VLAN_EXTEND)
+                       max_len += VLAN_TAG_SIZE;
+
+               E1000_WRITE_REG(hw, E1000_RLPML, max_len);
        } else
                rctl &= ~E1000_RCTL_LPE;
 
-- 
1.8.3.1