ixgbe: Fix - Do not allow Rx FC on 82598 at 1G due to errata

The 82598 has an erratum that receipt of pause frames at 1G
could lead to a Tx Hang.  To avoid this this patch disables
Rx FC while at 1G speed for all 82598 parts.

Signed-off-by: Don Skidmore <donald.c.skidmore@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ixgbe/ixgbe_82598.c b/drivers/net/ixgbe/ixgbe_82598.c
index 3103f4165311e4b32080731241a392a2573f6d18..35a06b47587bd2bf57a376bf4f95ee65a7c93c0e 100644 (file)
--- a/drivers/net/ixgbe/ixgbe_82598.c
+++ b/drivers/net/ixgbe/ixgbe_82598.c
@@ -357,12 +357,34 @@ static s32 ixgbe_fc_enable_82598(struct ixgbe_hw *hw, s32 packetbuf_num)
        u32 fctrl_reg;
        u32 rmcs_reg;
        u32 reg;
+       u32 link_speed = 0;
+       bool link_up;
 
 #ifdef CONFIG_DCB
        if (hw->fc.requested_mode == ixgbe_fc_pfc)
                goto out;
 
 #endif /* CONFIG_DCB */
+       /*
+        * On 82598 having Rx FC on causes resets while doing 1G
+        * so if it's on turn it off once we know link_speed. For
+        * more details see 82598 Specification update.
+        */
+       hw->mac.ops.check_link(hw, &link_speed, &link_up, false);
+       if (link_up && link_speed == IXGBE_LINK_SPEED_1GB_FULL) {
+               switch (hw->fc.requested_mode) {
+               case ixgbe_fc_full:
+                       hw->fc.requested_mode = ixgbe_fc_tx_pause;
+                       break;
+               case ixgbe_fc_rx_pause:
+                       hw->fc.requested_mode = ixgbe_fc_none;
+                       break;
+               default:
+                       /* no change */
+                       break;
+               }
+       }
+
        /* Negotiate the fc mode to use */
        ret_val = ixgbe_fc_autoneg(hw);
        if (ret_val)