Re: [PATCH 1/2] Revert "e1000e: fix cyclic resets at link up with active tx"

From: Oleksandr Natalenko
Date: Fri Apr 26 2019 - 10:11:34 EST


On Wed, Apr 17, 2019 at 11:13:16AM +0300, Konstantin Khlebnikov wrote:
> This reverts commit 0f9e980bf5ee1a97e2e401c846b2af989eb21c61.
>
> That change cased false-positive warning about hardware hang:
>
> e1000e: eth0 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: Rx/Tx
> IPv6: ADDRCONF(NETDEV_CHANGE): eth0: link becomes ready
> e1000e 0000:00:1f.6 eth0: Detected Hardware Unit Hang:
> TDH <0>
> TDT <1>
> next_to_use <1>
> next_to_clean <0>
> buffer_info[next_to_clean]:
> time_stamp <fffba7a7>
> next_to_watch <0>
> jiffies <fffbb140>
> next_to_watch.status <0>
> MAC Status <40080080>
> PHY Status <7949>
> PHY 1000BASE-T Status <0>
> PHY Extended Status <3000>
> PCI Status <10>
> e1000e: eth0 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: Rx/Tx
>
> Besides warning everything works fine.
> Original issue will be fixed property in following patch.
>
> Signed-off-by: Konstantin Khlebnikov <khlebnikov@xxxxxxxxxxxxxx>
> Reported-by: Joseph Yasi <joe.yasi@xxxxxxxxx>
> Link: https://bugzilla.kernel.org/show_bug.cgi?id=203175
> ---
> drivers/net/ethernet/intel/e1000e/netdev.c | 15 +++++++++------
> 1 file changed, 9 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c b/drivers/net/ethernet/intel/e1000e/netdev.c
> index 7acc61e4f645..ba96e52aa8d1 100644
> --- a/drivers/net/ethernet/intel/e1000e/netdev.c
> +++ b/drivers/net/ethernet/intel/e1000e/netdev.c
> @@ -5309,13 +5309,8 @@ static void e1000_watchdog_task(struct work_struct *work)
> /* 8000ES2LAN requires a Rx packet buffer work-around
> * on link down event; reset the controller to flush
> * the Rx packet buffer.
> - *
> - * If the link is lost the controller stops DMA, but
> - * if there is queued Tx work it cannot be done. So
> - * reset the controller to flush the Tx packet buffers.
> */
> - if ((adapter->flags & FLAG_RX_NEEDS_RESTART) ||
> - e1000_desc_unused(tx_ring) + 1 < tx_ring->count)
> + if (adapter->flags & FLAG_RX_NEEDS_RESTART)
> adapter->flags |= FLAG_RESTART_NOW;
> else
> pm_schedule_suspend(netdev->dev.parent,
> @@ -5338,6 +5333,14 @@ static void e1000_watchdog_task(struct work_struct *work)
> adapter->gotc_old = adapter->stats.gotc;
> spin_unlock(&adapter->stats64_lock);
>
> + /* If the link is lost the controller stops DMA, but
> + * if there is queued Tx work it cannot be done. So
> + * reset the controller to flush the Tx packet buffers.
> + */
> + if (!netif_carrier_ok(netdev) &&
> + (e1000_desc_unused(tx_ring) + 1 < tx_ring->count))
> + adapter->flags |= FLAG_RESTART_NOW;
> +
> /* If reset is necessary, do it outside of interrupt context. */
> if (adapter->flags & FLAG_RESTART_NOW) {
> schedule_work(&adapter->reset_task);
>

Tested-by: Oleksandr Natalenko <oleksandr@xxxxxxxxxx>

--
Best regards,
Oleksandr Natalenko (post-factum)
Senior Software Maintenance Engineer