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

[Anatoly Burakov <anatoly.burakov@intel.com>]

From: Krzysztof Galazka <krzysztof.galazka@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.galazka@intel.com>
Reviewed-by: Jan Sokolowski <jan.sokolowski@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