[RFC] app/testpmd: use RSS conf from software when configuring DCB

[Min Zhou <zhoumin@loongson.cn>]

In the testpmd command, we have to stop the port firstly before configuring
the DCB. However, some PMDs may execute a hardware reset during the port
stop, such as ixgbe. Some kind of reset operations of PMD could clear the
configurations of RSS in the hardware register. This would cause the loss
of RSS configurations that were set during the testpmd initialization. As
a result, I find that I cannot enable RSS and DCB at the same time in the
testpmd command when using Intel 82599 NIC.

Although this patch can solve the problem I encountered, is there any risk
of using rss conf from software instead of reading from the hardware
register when configuring DCB?

Signed-off-by: Min Zhou <zhoumin@loongson.cn>
---
 app/test-pmd/testpmd.c | 11 +----------
 1 file changed, 1 insertion(+), 10 deletions(-)

diff --git a/app/test-pmd/testpmd.c b/app/test-pmd/testpmd.c
index 5cb6f92523..3c382267b8 100644
--- a/app/test-pmd/testpmd.c
+++ b/app/test-pmd/testpmd.c
@@ -4247,14 +4247,12 @@ const uint16_t vlan_tags[] = {
 };
 
 static  int
-get_eth_dcb_conf(portid_t pid, struct rte_eth_conf *eth_conf,
+get_eth_dcb_conf(portid_t pid __rte_unused, struct rte_eth_conf *eth_conf,
 		 enum dcb_mode_enable dcb_mode,
 		 enum rte_eth_nb_tcs num_tcs,
 		 uint8_t pfc_en)
 {
 	uint8_t i;
-	int32_t rc;
-	struct rte_eth_rss_conf rss_conf;
 
 	/*
 	 * Builds up the correct configuration for dcb+vt based on the vlan tags array
@@ -4296,12 +4294,6 @@ get_eth_dcb_conf(portid_t pid, struct rte_eth_conf *eth_conf,
 		struct rte_eth_dcb_tx_conf *tx_conf =
 				&eth_conf->tx_adv_conf.dcb_tx_conf;
 
-		memset(&rss_conf, 0, sizeof(struct rte_eth_rss_conf));
-
-		rc = rte_eth_dev_rss_hash_conf_get(pid, &rss_conf);
-		if (rc != 0)
-			return rc;
-
 		rx_conf->nb_tcs = num_tcs;
 		tx_conf->nb_tcs = num_tcs;
 
@@ -4313,7 +4305,6 @@ get_eth_dcb_conf(portid_t pid, struct rte_eth_conf *eth_conf,
 		eth_conf->rxmode.mq_mode =
 				(enum rte_eth_rx_mq_mode)
 					(rx_mq_mode & RTE_ETH_MQ_RX_DCB_RSS);
-		eth_conf->rx_adv_conf.rss_conf = rss_conf;
 		eth_conf->txmode.mq_mode = RTE_ETH_MQ_TX_DCB;
 	}
 
-- 
2.31.1