From 21d882eb3a7e8d706247f32c0352390791751e8f Mon Sep 17 00:00:00 2001 From: Emil Tantilov Date: Mon, 26 Sep 2016 14:08:18 -0700 Subject: [PATCH] ixgbe: fix link status check for copper X550em Read the PHY register twice in order to get the correct value for autoneg_status. Signed-off-by: Emil Tantilov Tested-by: Krishneil Singh Signed-off-by: Jeff Kirsher --- drivers/net/ethernet/intel/ixgbe/ixgbe_x550.c | 21 +++++++++++++-------- 1 file changed, 13 insertions(+), 8 deletions(-) diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_x550.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_x550.c index e9fa83b..51b6ade 100644 --- a/drivers/net/ethernet/intel/ixgbe/ixgbe_x550.c +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_x550.c @@ -1556,7 +1556,7 @@ static s32 ixgbe_check_link_t_X550em(struct ixgbe_hw *hw, bool link_up_wait_to_complete) { u32 status; - u16 autoneg_status; + u16 i, autoneg_status; if (hw->mac.ops.get_media_type(hw) != ixgbe_media_type_copper) return IXGBE_ERR_CONFIG; @@ -1568,13 +1568,18 @@ static s32 ixgbe_check_link_t_X550em(struct ixgbe_hw *hw, if (status || !(*link_up)) return status; - /* MAC link is up, so check external PHY link. - * Read this twice back to back to indicate current status. - */ - status = hw->phy.ops.read_reg(hw, MDIO_STAT1, MDIO_MMD_AN, - &autoneg_status); - if (status) - return status; + /* MAC link is up, so check external PHY link. + * Link status is latching low, and can only be used to detect link + * drop, and not the current status of the link without performing + * back-to-back reads. + */ + for (i = 0; i < 2; i++) { + status = hw->phy.ops.read_reg(hw, MDIO_STAT1, MDIO_MMD_AN, + &autoneg_status); + + if (status) + return status; + } /* If external PHY link is not up, then indicate link not up */ if (!(autoneg_status & IXGBE_MDIO_AUTO_NEG_LINK_STATUS)) -- 2.7.4