[PATCH] e1000: Fix TX queue length based on link speed

10/100 speeds seem to have some problems reporting false tx timeouts especially at half duplex.  Fixed by using a timeout factor to attempt to mitigate the false timeouts.

Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Signed-off-by: John Ronciak <john.ronciak@intel.com>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>

drivers/net/e1000/e1000.h

@@ -296,6 +296,7 @@ struct e1000_adapter {
 	uint32_t tx_fifo_head;
 	uint32_t tx_head_addr;
 	uint32_t tx_fifo_size;
+	uint8_t  tx_timeout_factor;
 	atomic_t tx_fifo_stall;
 	boolean_t pcix_82544;
 	boolean_t detect_tx_hung;

drivers/net/e1000/e1000_main.c

@@ -2319,6 +2319,21 @@ e1000_watchdog_task(struct e1000_adapter *adapter)
 			       adapter->link_duplex == FULL_DUPLEX ?
 			       "Full Duplex" : "Half Duplex");
 
+			/* tweak tx_queue_len according to speed/duplex */
+			netdev->tx_queue_len = adapter->tx_queue_len;
+			adapter->tx_timeout_factor = 1;
+			if (adapter->link_duplex == HALF_DUPLEX) {
+				switch (adapter->link_speed) {
+				case SPEED_10:
+					netdev->tx_queue_len = 10;
+					adapter->tx_timeout_factor = 8;
+					break;
+				case SPEED_100:
+					netdev->tx_queue_len = 100;
+					break;
+				}
+			}
+
 			netif_carrier_on(netdev);
 			netif_wake_queue(netdev);
 			mod_timer(&adapter->phy_info_timer, jiffies + 2 * HZ);