[PATCH net-drivers-2.6 6/10] e1000: Patch from Peter Kjellstroem -- fix lockup with 82547

[Malli Chilakala <mallikarjuna.chilakala@xxxxxxxxx>]

6 Patch from Peter Kjellstroem -- fix lockup with 82547
Signed-off-by: Mallikarjuna R Chilakala <mallikarjuna.chilakala@xxxxxxxxx>
Signed-off-by: Ganesh Venkatesan <ganesh.venkatesan@xxxxxxxxx>
Signed-off-by: John Ronciak <john.ronciak@xxxxxxxxx>
diff -up net-drivers-2.6/drivers/net/e1000/e1000_main.c 
net-drivers-2.6/drivers/net/e1000.new/e1000_main.c
--- net-drivers-2.6/drivers/net/e1000/e1000_main.c      2005-02-01 
23:10:24.989105880 -0800
+++ net-drivers-2.6/drivers/net/e1000.new/e1000_main.c  2005-02-01 
23:10:26.709844288 -0800
@@ -2165,10 +2165,28 @@ e1000_intr(int irq, void *data, struct p
                __netif_rx_schedule(netdev);
        }
 #else
+       /* Writing IMC and IMS is needed for 82547.
+          Due to Hub Link bus being occupied, an interrupt
+          de-assertion message is not able to be sent.
+          When an interrupt assertion message is generated later,
+          two messages are re-ordered and sent out.
+          That causes APIC to think 82547 is in de-assertion
+          state, while 82547 is in assertion state, resulting
+          in dead lock. Writing IMC forces 82547 into
+          de-assertion state.
+       */
+       if(hw->mac_type == e1000_82547 || hw->mac_type == e1000_82547_rev_2){
+               atomic_inc(&adapter->irq_sem);
+               E1000_WRITE_REG(&adapter->hw, IMC, ~0);
+       }
+
        for(i = 0; i < E1000_MAX_INTR; i++)
                if(unlikely(!e1000_clean_rx_irq(adapter) &
                   !e1000_clean_tx_irq(adapter)))
                        break;
+
+       if(hw->mac_type == e1000_82547 || hw->mac_type == e1000_82547_rev_2)
+               e1000_irq_enable(adapter);
 #endif
 
        return IRQ_HANDLED;