[PATCH 2.6 2/9] ixgb: Limit number of Rx descriptors to 512

[Ganesh Venkatesan <ganesh.venkatesan@xxxxxxxxx>]

Signed-off-by: Ganesh Venkatesan <ganesh.venkatesan@xxxxxxxxx>
diff -up net-drivers-2.6/drivers/net/ixgb/ixgb.h 
net-drivers-2.6/drivers/net/ixgb.new/ixgb.h
--- net-drivers-2.6/drivers/net/ixgb/ixgb.h     2005-01-05 17:13:27.000000000 
-0800
+++ net-drivers-2.6/drivers/net/ixgb.new/ixgb.h 2005-01-05 17:13:28.000000000 
-0800
@@ -91,9 +91,14 @@ struct ixgb_adapter;
 #define MAX_TXD        4096
 #define MIN_TXD        64
 
-#define DEFAULT_RXD    1024
-#define MAX_RXD        4096
 #define MIN_RXD        64
+/* hardware cannot reliably support more than 512 descriptors owned by
+ * hardware descriptor cache otherwise an unreliable ring under heavy 
+ * recieve load may result */
+/* #define DEFAULT_RXD   1024 */
+/* #define MAX_RXD        4096 */
+#define DEFAULT_RXD    512
+#define MAX_RXD        512
 
 /* Supported Rx Buffer Sizes */
 #define IXGB_RXBUFFER_2048  2048