r8169: RxFIFO overflow oddities with 8168 chipsets.

Some experiment-based action to prevent my 8168 chipsets locking-up hard
in the irq handler under load (pktgen ~1Mpps). Apparently a reset is not
always mandatory (is it at all ?).

- RTL_GIGA_MAC_VER_12
- RTL_GIGA_MAC_VER_25
  Missed ~55% packets. Note:
  - this is an old SiS 965L motherboard
  - the 8168 chipset emits (lots of) control frames towards the sender

- RTL_GIGA_MAC_VER_26
  The chipset does not go into a frenzy of mac control pause when it
  crashes yet but it can still be crashed. It needs more work.

Signed-off-by: Francois Romieu <romieu@fr.zoreil.com>
Cc: Ivan Vecera <ivecera@redhat.com>
Cc: Hayes <hayeswang@realtek.com>

1 files changed, 21 insertions, 9 deletions

diff --git a/drivers/net/r8169.c b/drivers/net/r8169.c
index 9ab3b43c7d04..40dabe2b3dae 100644
--- a/drivers/net/r8169.c
+++ b/drivers/net/r8169.c
@@ -973,7 +973,8 @@ static void __rtl8169_check_link_status(struct net_device *dev,
                 if (pm)
                         pm_request_resume(&tp->pci_dev->dev);
                 netif_carrier_on(dev);
-                netif_info(tp, ifup, dev, "link up\n");
+                if (net_ratelimit())
+                        netif_info(tp, ifup, dev, "link up\n");
         } else {
                 netif_carrier_off(dev);
                 netif_info(tp, ifdown, dev, "link down\n");
@@ -4640,13 +4641,24 @@ static irqreturn_t rtl8169_interrupt(int irq, void *dev_instance)
                         break;
                 }
 
-                /* Work around for rx fifo overflow */
-                if (unlikely(status & RxFIFOOver) &&
-                    (tp->mac_version == RTL_GIGA_MAC_VER_11 ||
-                     tp->mac_version == RTL_GIGA_MAC_VER_22)) {
-                        netif_stop_queue(dev);
-                        rtl8169_tx_timeout(dev);
-                        break;
+                if (unlikely(status & RxFIFOOver)) {
+                        switch (tp->mac_version) {
+                        /* Work around for rx fifo overflow */
+                        case RTL_GIGA_MAC_VER_11:
+                        case RTL_GIGA_MAC_VER_22:
+                        case RTL_GIGA_MAC_VER_26:
+                                netif_stop_queue(dev);
+                                rtl8169_tx_timeout(dev);
+                                goto done;
+                        /* Experimental science. Pktgen proof. */
+                        case RTL_GIGA_MAC_VER_12:
+                        case RTL_GIGA_MAC_VER_25:
+                                if (status == RxFIFOOver)
+                                        goto done;
+                                break;
+                        default:
+                                break;
+                        }
                 }
 
                 if (unlikely(status & SYSErr)) {
@@ -4682,7 +4694,7 @@ static irqreturn_t rtl8169_interrupt(int irq, void *dev_instance)
                         (status & RxFIFOOver) ? (status | RxOverflow) : status);
                 status = RTL_R16(IntrStatus);
         }
-
+done:
         return IRQ_RETVAL(handled);
 }