[PATCH v1 15/22] net/ixgbe/base: filter out spurious link up indication

[Anatoly Burakov]

From: Krzysztof Galazka <krzysztof.gala...@intel.com>

Extend SFP+ cage crosstalk fix by re-checking link state
after 5ms delay to filter out spurious link up indication
by transceiver with no fibre cable connected.

Signed-off-by: Krzysztof Galazka <krzysztof.gala...@intel.com>
Reviewed-by: Jan Sokolowski <jan.sokolow...@intel.com>
---
 drivers/net/ixgbe/base/ixgbe_common.c | 19 +++++++++++++++++--
 1 file changed, 17 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ixgbe/base/ixgbe_common.c 
b/drivers/net/ixgbe/base/ixgbe_common.c
index bb6e72fbe6..a19f4d715c 100644
--- a/drivers/net/ixgbe/base/ixgbe_common.c
+++ b/drivers/net/ixgbe/base/ixgbe_common.c
@@ -4194,10 +4194,25 @@ s32 ixgbe_check_mac_link_generic(struct ixgbe_hw *hw, 
ixgbe_link_speed *speed,
                        links_reg = IXGBE_READ_REG(hw, IXGBE_LINKS);
                }
        } else {
-               if (links_reg & IXGBE_LINKS_UP)
+               if (links_reg & IXGBE_LINKS_UP) {
+                       if (ixgbe_need_crosstalk_fix(hw)) {
+                               /* Check the link state again after a delay
+                                * to filter out spurious link up
+                                * notifications.
+                                */
+                               msec_delay(5);
+                               links_reg = IXGBE_READ_REG(hw, IXGBE_LINKS);
+                               if (!(links_reg & IXGBE_LINKS_UP)) {
+                                       *link_up = false;
+                                       *speed = IXGBE_LINK_SPEED_UNKNOWN;
+                                       return IXGBE_SUCCESS;
+                               }
+
+                       }
                        *link_up = true;
-               else
+               } else {
                        *link_up = false;
+               }
        }
 
        switch (links_reg & IXGBE_LINKS_SPEED_82599) {
-- 
2.43.0