nve(4) timeout fix

[Yuri Pankov]

Nathan Whitehorn wrote:
> Also on the subject of nVidia NICs, I've fixed the device timeout
> problem on nve(4). It appears that some revisions of the hardware don't
> send interrupts on tx completion, which caused watchdog timeouts under
> low load. We should take this hardware quirk into account for the nfe
> port as well.
> -Nathan
> 
> --- if_nve_original.c   Wed Apr 26 22:23:14 2006
> +++ if_nve.c    Wed Apr 26 21:52:34 2006
> @@ -1270,6 +1270,18 @@
>  nve_watchdog(struct ifnet *ifp)
>  {
>         struct nve_softc *sc = ifp->if_softc;
> +
> +       NVE_LOCK(sc);
> +       /* Check for lost interrupts -- happens on nForce4 */
> +       sc->hwapi->pfnDisableInterrupts(sc->hwapi->pADCX);
> +       sc->hwapi->pfnHandleInterrupt(sc->hwapi->pADCX);
> +       sc->hwapi->pfnEnableInterrupts(sc->hwapi->pADCX);
> +
> +       if (sc->pending_txs == 0) {
> +               NVE_UNLOCK(sc);
> +               return; /* Problem went away */
> +       }
> +       NVE_UNLOCK(sc);
> 
>         device_printf(sc->dev, "device timeout (%d)\n", sc->pending_txs);
> 

Indeed, it seems to solve timeout() messages. Haven't got any so far. 
Thank you!

one small correction - this patch doesn't apply cleanly to -current 
source, so I've patched source by hand and here's patch for -current:

--- if_nve.c.orig       Mon Dec 12 09:23:43 2005
+++ if_nve.c    Thu Apr 27 18:23:48 2006
@@ -1277,6 +1277,18 @@
  {
         struct nve_softc *sc = ifp->if_softc;

+       NVE_LOCK(sc);
+       /* Check for lost interrupts -- happens on nForce4 */
+       sc->hwapi->pfnDisableInterrupts(sc->hwapi->pADCX);
+       sc->hwapi->pfnHandleInterrupt(sc->hwapi->pADCX);
+       sc->hwapi->pfnEnableInterrupts(sc->hwapi->pADCX);
+
+       if (sc->pending_txs == 0) {
+               NVE_UNLOCK(sc);
+               return; /* Problem went away */
+       }
+       NVE_UNLOCK(sc);
+
         device_printf(sc->dev, "device timeout (%d)\n", c->pending_txs);

         NVE_LOCK(sc);

Yuri