Commit 4d24136c authored by Bruce Allan's avatar Bruce Allan Committed by Jeff Kirsher
Browse files

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: default avatarBruce Allan <>
Tested-by: default avatarAaron Brown <>
Signed-off-by: default avatarJeff Kirsher <>
parent 56032be7
......@@ -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,
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,
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);
return ret_val;
Markdown is supported
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment