ENGR00223533 - FEC : fix net watchdog timeout due not refreshing TX timers

When do overnight gpu stress test throught nfs, kernel dump as below:

------------[ cut here ]------------
WARNING: at net/sched/sch_generic.c:255 dev_watchdog+0x284/0x2a8()
NETDEV WATCHDOG: eth0 (fec): transmit queue 0 timed out
Modules linked in: galcore imx2_wd_test [last unloaded: galcore]
[<80045854>] (unwind_backtrace+0x0/0xf8) from [<80070c2c>]
(warn_slowpath_common+0x4c/0x64)
<snip>

In sometime, ethernet cannot recover after watchdog timeout which
results in nfs no responding and system hang on.

The patch fixes the way that ->trans_start is refreshed to avoid watchdog
timeout during ethernet status change (such as speed, duplex), and re-init
fec to recover ethernet after watchdog timeout.

Signed-off-by: Fugang Duan  <B38611@freescale.com>

diff --git a/drivers/net/fec.c b/drivers/net/fec.c
index 5af378f391eed24e17df90de8a83793f4709d7b7..86e4ea3404b39e0866fe2f7620aa77c1437d19d1 100755 (executable)
--- a/drivers/net/fec.c
+++ b/drivers/net/fec.c
@@ -397,7 +397,12 @@ fec_timeout(struct net_device *ndev)
 
        ndev->stats.tx_errors++;
 
+       netif_device_detach(ndev);
+       fec_stop(ndev);
+
        fec_restart(ndev, fep->full_duplex);
+       netif_device_attach(ndev);
+       ndev->trans_start = jiffies; /* prevent tx timeout */
        if (fep->link && !fep->tx_full)
                netif_wake_queue(ndev);
 }
@@ -1320,10 +1325,7 @@ fec_enet_close(struct net_device *ndev)
 {
        struct fec_enet_private *fep = netdev_priv(ndev);
 
-       /* Don't know what to do yet. */
        fep->opened = 0;
-       netif_stop_queue(ndev);
-       netif_carrier_off(ndev);
        if (fep->use_napi)
                napi_disable(&fep->napi);
 
@@ -1760,7 +1762,10 @@ fec_stop(struct net_device *dev)
        if (fep->ptimer_present)
                fec_ptp_stop(fep->ptp_priv);
        writel(FEC_DEFAULT_IMASK, fep->hwp + FEC_IMASK);
-       netif_stop_queue(dev);
+
+       if (netif_running(dev))
+               netif_stop_queue(dev);
+       netif_carrier_off(dev);     /* prevent tx timeout */
        fep->link = 0;
 }
 
@@ -1921,7 +1926,6 @@ fec_suspend(struct device *dev)
        if (netif_running(ndev)) {
                netif_device_detach(ndev);
                fec_stop(ndev);
-               netif_carrier_off(ndev);
                clk_disable(fep->clk);
        }