igb: When GbE link up, wait for Remote receiver status condition

I210 device IPv6 autoconf test sometimes fails,
because DAD NS for link-local is not transmitted.
This packet is silently dropped.
This problem is seen only GbE environment.

igb_watchdog_task link up detection continues to the following process.
The following cases are observed:
1.PHY 1000BASE-T Status Register Remote receiver status bit is NG.
(NG status becomes OK after about 200 - 700ms)
2.In this case, the transfer packet is silently dropped.

1000BASE-T Status register
[Expected]: 0x3800 or 0x7800
[problem occurred]: 0x2800 or 0x6800
Frequency of occurrence: approx 1/10 - 1/40 observed

In order to avoid this problem,
wait until 1000BASE-T Status register "Remote receiver status OK"

After applying this patch, at least 400 runs succeed with no problems.

Signed-off-by: Takuma Ueba <t.ueba11@gmail.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c
index af46fcf..1aa0180 100644 (file)
--- a/drivers/net/ethernet/intel/igb/igb_main.c
+++ b/drivers/net/ethernet/intel/igb/igb_main.c
@@ -4357,6 +4357,7 @@ static void igb_watchdog_task(struct work_struct *work)
        u32 link;
        int i;
        u32 connsw;
+       u16 phy_data, retry_count = 20;
 
        link = igb_has_link(adapter);
 
@@ -4435,6 +4436,25 @@ static void igb_watchdog_task(struct work_struct *work)
                                break;
                        }
 
+                       if (adapter->link_speed != SPEED_1000)
+                               goto no_wait;
+
+                       /* wait for Remote receiver status OK */
+retry_read_status:
+                       if (!igb_read_phy_reg(hw, PHY_1000T_STATUS,
+                                             &phy_data)) {
+                               if (!(phy_data & SR_1000T_REMOTE_RX_STATUS) &&
+                                   retry_count) {
+                                       msleep(100);
+                                       retry_count--;
+                                       goto retry_read_status;
+                               } else if (!retry_count) {
+                                       dev_err(&adapter->pdev->dev, "exceed max 2 second\n");
+                               }
+                       } else {
+                               dev_err(&adapter->pdev->dev, "read 1000Base-T Status Reg\n");
+                       }
+no_wait:
                        netif_carrier_on(netdev);
 
                        igb_ping_all_vfs(adapter);