From 4d24136c8ea03ecfdb6b8256571da8b520b92d8b Mon Sep 17 00:00:00 2001 From: Bruce Allan Date: Fri, 16 Dec 2011 00:46:06 +0000 Subject: [PATCH] e1000e: 82579: workaround for link drop issue When connected to certain switches, the 82579 PHY might drop link unexpectedly. Work around the issue by setting the Mean Square Error higher than the hardware default. Signed-off-by: Bruce Allan Tested-by: Aaron Brown Signed-off-by: Jeff Kirsher --- drivers/net/ethernet/intel/e1000e/ich8lan.c | 22 +++++++++++++++++++++ 1 file changed, 22 insertions(+) diff --git a/drivers/net/ethernet/intel/e1000e/ich8lan.c b/drivers/net/ethernet/intel/e1000e/ich8lan.c index e2a80a283fd3..1b69c2d6b417 100644 --- a/drivers/net/ethernet/intel/e1000e/ich8lan.c +++ b/drivers/net/ethernet/intel/e1000e/ich8lan.c @@ -145,6 +145,8 @@ #define I82579_EMI_ADDR 0x10 #define I82579_EMI_DATA 0x11 #define I82579_LPI_UPDATE_TIMER 0x4805 /* in 40ns units + 40 ns base value */ +#define I82579_MSE_THRESHOLD 0x084F /* Mean Square Error Threshold */ +#define I82579_MSE_LINK_DOWN 0x2411 /* MSE count before dropping link */ /* Strapping Option Register - RO */ #define E1000_STRAP 0x0000C @@ -1669,6 +1671,26 @@ static s32 e1000_lv_phy_workarounds_ich8lan(struct e1000_hw *hw) /* Set MDIO slow mode before any other MDIO access */ ret_val = e1000_set_mdio_slow_mode_hv(hw); + ret_val = hw->phy.ops.acquire(hw); + if (ret_val) + goto out; + ret_val = hw->phy.ops.write_reg_locked(hw, I82579_EMI_ADDR, + I82579_MSE_THRESHOLD); + if (ret_val) + goto release; + /* set MSE higher to enable link to stay up when noise is high */ + ret_val = hw->phy.ops.write_reg_locked(hw, I82579_EMI_DATA, 0x0034); + if (ret_val) + goto release; + ret_val = hw->phy.ops.write_reg_locked(hw, I82579_EMI_ADDR, + I82579_MSE_LINK_DOWN); + if (ret_val) + goto release; + /* drop link after 5 times MSE threshold was reached */ + ret_val = hw->phy.ops.write_reg_locked(hw, I82579_EMI_DATA, 0x0005); +release: + hw->phy.ops.release(hw); + out: return ret_val; } -- 2.20.1