[PATCH v2] e1000e: Make speed detection on hotplugging cable more reliable

From: Kai-Heng Feng
Date: Mon Jul 15 2019 - 08:26:11 EST


After hotplugging an 1Gbps ethernet cable with 1Gbps link partner, the
MII_BMSR may report 10Mbps, renders the network rather slow.

The issue has much lower fail rate after commit 59653e6497d1 ("e1000e:
Make watchdog use delayed work"), which essentially introduces some
delay before running the watchdog task.

But there's still a chance that the hotplugging event and the queued
watchdog task gets run at the same time, then the original issue can be
observed once again.

So let's use mod_delayed_work() to add a deterministic 1 second delay
before running watchdog task, after an interrupt.

Signed-off-by: Kai-Heng Feng <kai.heng.feng@xxxxxxxxxxxxx>
---
drivers/net/ethernet/intel/e1000e/netdev.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c b/drivers/net/ethernet/intel/e1000e/netdev.c
index e4baa13b3cda..c83bf5349d53 100644
--- a/drivers/net/ethernet/intel/e1000e/netdev.c
+++ b/drivers/net/ethernet/intel/e1000e/netdev.c
@@ -1780,8 +1780,8 @@ static irqreturn_t e1000_intr_msi(int __always_unused irq, void *data)
}
/* guard against interrupt when we're going down */
if (!test_bit(__E1000_DOWN, &adapter->state))
- queue_delayed_work(adapter->e1000_workqueue,
- &adapter->watchdog_task, 1);
+ mod_delayed_work(adapter->e1000_workqueue,
+ &adapter->watchdog_task, HZ);
}

/* Reset on uncorrectable ECC error */
@@ -1861,8 +1861,8 @@ static irqreturn_t e1000_intr(int __always_unused irq, void *data)
}
/* guard against interrupt when we're going down */
if (!test_bit(__E1000_DOWN, &adapter->state))
- queue_delayed_work(adapter->e1000_workqueue,
- &adapter->watchdog_task, 1);
+ mod_delayed_work(adapter->e1000_workqueue,
+ &adapter->watchdog_task, HZ);
}

/* Reset on uncorrectable ECC error */
@@ -1907,8 +1907,8 @@ static irqreturn_t e1000_msix_other(int __always_unused irq, void *data)
hw->mac.get_link_status = true;
/* guard against interrupt when we're going down */
if (!test_bit(__E1000_DOWN, &adapter->state))
- queue_delayed_work(adapter->e1000_workqueue,
- &adapter->watchdog_task, 1);
+ mod_delayed_work(adapter->e1000_workqueue,
+ &adapter->watchdog_task, HZ);
}

if (!test_bit(__E1000_DOWN, &adapter->state))
--
2.17.1