[PATCH] e1000: Implement a workaround for 82546 errata 10

Implement 82546 errata 10 --  first Tx descriptor cannot have more than 2015 byte of data in it or it could hang the transmitter.

Signed-off-by: Mallikarjuna R Chilakala <mallikarjuna.chilakala@intel.com>
Signed-off-by: Ganesh Venkatesan <ganesh.venkatesan@intel.com>
Signed-off-by: John Ronciak <john.ronciak@intel.com>
diff -up net-drivers-2.6/drivers/net/e1000/e1000_main.c net-drivers-2.6/drivers/net/e1000.new/e1000_main.c

1 files changed, 16 insertions, 0 deletions

diff --git a/drivers/net/e1000/e1000_main.c b/drivers/net/e1000/e1000_main.c
index 479915a9f0fb..e54890aff5f1 100644
--- a/drivers/net/e1000/e1000_main.c
+++ b/drivers/net/e1000/e1000_main.c
@@ -1777,6 +1777,15 @@ e1000_tx_map(struct e1000_adapter *adapter, struct sk_buff *skb,
                 if(unlikely(mss && !nr_frags && size == len && size > 8))
                         size -= 4;
 #endif
+                /* work-around for errata 10 and it applies
+                 * to all controllers in PCI-X mode
+                 * The fix is to make sure that the first descriptor of a
+                 * packet is smaller than 2048 - 16 - 16 (or 2016) bytes
+                 */
+                if(unlikely((adapter->hw.bus_type == e1000_bus_type_pcix) &&
+                                (size > 2015) && count == 0))
+                        size = 2015;
+                                                                                
                 /* Workaround for potential 82544 hang in PCI-X.  Avoid
                  * terminating buffers within evenly-aligned dwords. */
                 if(unlikely(adapter->pcix_82544 &&
@@ -1979,6 +1988,13 @@ e1000_xmit_frame(struct sk_buff *skb, struct net_device *netdev)
         if(adapter->pcix_82544)
                 count++;
 
+        /* work-around for errata 10 and it applies to all controllers 
+         * in PCI-X mode, so add one more descriptor to the count
+         */
+        if(unlikely((adapter->hw.bus_type == e1000_bus_type_pcix) &&
+                        (len > 2015)))
+                count++;
+
         nr_frags = skb_shinfo(skb)->nr_frags;
         for(f = 0; f < nr_frags; f++)
                 count += TXD_USE_COUNT(skb_shinfo(skb)->frags[f].size,