cxgb4 : Handle dcb enable correctly

Disabling DCBx in firmware automatically enables DCBx for control via host
lldp agents. Wait for an explicit setstate call from an lldp agents to enable
 DCBx instead.

Fixes: 76bcb31efc06 ("cxgb4 : Add DCBx support codebase and dcbnl_ops")

Signed-off-by: Anish Bhatt <anish@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 11 insertions, 2 deletions

diff --git a/drivers/net/ethernet/chelsio/cxgb4/cxgb4_dcb.c b/drivers/net/ethernet/chelsio/cxgb4/cxgb4_dcb.c
index ee819fd12bd2..6fe300e316c3 100644
--- a/drivers/net/ethernet/chelsio/cxgb4/cxgb4_dcb.c
+++ b/drivers/net/ethernet/chelsio/cxgb4/cxgb4_dcb.c
@@ -116,7 +116,6 @@ void cxgb4_dcb_state_fsm(struct net_device *dev,
                         /* we're going to use Host DCB */
                         dcb->state = CXGB4_DCB_STATE_HOST;
                         dcb->supported = CXGB4_DCBX_HOST_SUPPORT;
-                        dcb->enabled = 1;
                         break;
                 }
 
@@ -386,6 +385,12 @@ static u8 cxgb4_setstate(struct net_device *dev, u8 enabled)
 {
         struct port_info *pi = netdev2pinfo(dev);
 
+        /* If DCBx is host-managed, dcb is enabled by outside lldp agents */
+        if (pi->dcb.state == CXGB4_DCB_STATE_HOST) {
+                pi->dcb.enabled = enabled;
+                return 0;
+        }
+
         /* Firmware doesn't provide any mechanism to control the DCB state.
          */
         if (enabled != (pi->dcb.state == CXGB4_DCB_STATE_FW_ALLSYNCED))
diff --git a/drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c b/drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c
index 3f60070f2519..97683c1c5b69 100644
--- a/drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c
+++ b/drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c
@@ -694,7 +694,11 @@ int cxgb4_dcb_enabled(const struct net_device *dev)
 #ifdef CONFIG_CHELSIO_T4_DCB
         struct port_info *pi = netdev_priv(dev);
 
-        return pi->dcb.state == CXGB4_DCB_STATE_FW_ALLSYNCED;
+        if (!pi->dcb.enabled)
+                return 0;
+
+        return ((pi->dcb.state == CXGB4_DCB_STATE_FW_ALLSYNCED) ||
+                (pi->dcb.state == CXGB4_DCB_STATE_HOST));
 #else
         return 0;
 #endif