[dpdk-stable] [PATCH] net/igc: fix Rx packet size error

[Alvin Zhang]

When DEV_RX_OFFLOAD_KEEP_CRC is enabled, the PMD will minus 4 bytes
of CRC from the size of a packet, but the NIC will strip the CRC
because the CRC strip bit in DVMOLR register is not cleared. This
will cause the size of a packet to be 4 bytes less.

This patch updates the CRC strip bit according to whether
DEV_RX_OFFLOAD_KEEP_CRC is enabled.

Fixes: a5aeb2b9e225 ("net/igc: support Rx and Tx")
Cc: stable at dpdk.org

Signed-off-by: Alvin Zhang <alvinx.zhang at intel.com>
---
 drivers/net/igc/igc_txrx.c | 22 +++++++++++++---------
 1 file changed, 13 insertions(+), 9 deletions(-)

diff --git a/drivers/net/igc/igc_txrx.c b/drivers/net/igc/igc_txrx.c
index c0a5d5e..68b102d 100644
--- a/drivers/net/igc/igc_txrx.c
+++ b/drivers/net/igc/igc_txrx.c
@@ -1290,20 +1290,24 @@ int eth_igc_rx_descriptor_status(void *rx_queue, uint16_t offset)
 	 * This needs to be done after enable.
 	 */
 	for (i = 0; i < dev->data->nb_rx_queues; i++) {
+		uint32_t dvmolr;
+
 		rxq = dev->data->rx_queues[i];
 		IGC_WRITE_REG(hw, IGC_RDH(rxq->reg_idx), 0);
-		IGC_WRITE_REG(hw, IGC_RDT(rxq->reg_idx),
-				rxq->nb_rx_desc - 1);
+		IGC_WRITE_REG(hw, IGC_RDT(rxq->reg_idx), rxq->nb_rx_desc - 1);
+
+		dvmolr = IGC_READ_REG(hw, IGC_DVMOLR(rxq->queue_id));
 
 		/* strip queue vlan offload */
-		if (rxq->offloads & DEV_RX_OFFLOAD_VLAN_STRIP) {
-			uint32_t dvmolr;
-			dvmolr = IGC_READ_REG(hw, IGC_DVMOLR(rxq->queue_id));
+		dvmolr = (rxq->offloads & DEV_RX_OFFLOAD_VLAN_STRIP) ?
+			 (dvmolr | IGC_DVMOLR_STRVLAN) :
+			 (dvmolr & ~IGC_DVMOLR_STRVLAN);
 
-			/* If vlan been stripped off, the CRC is meaningless. */
-			dvmolr |= IGC_DVMOLR_STRVLAN | IGC_DVMOLR_STRCRC;
-			IGC_WRITE_REG(hw, IGC_DVMOLR(rxq->reg_idx), dvmolr);
-		}
+		dvmolr = (offloads & DEV_RX_OFFLOAD_KEEP_CRC) ?
+			 (dvmolr & ~IGC_DVMOLR_STRCRC) :
+			 (dvmolr | IGC_DVMOLR_STRCRC);
+
+		IGC_WRITE_REG(hw, IGC_DVMOLR(rxq->reg_idx), dvmolr);
 	}
 
 	return 0;
-- 
1.8.3.1