Index: sys/dev/e1000/if_em.h
===================================================================
--- sys/dev/e1000/if_em.h
+++ sys/dev/e1000/if_em.h
@@ -249,6 +249,14 @@
  * solve it just using this define.
  */
 #define EM_EIAC 0x000DC
+/*
+ * 82574 only reports 3 MSI-X vectors by default;
+ * defines assisting with making it report 5 are
+ * located here.
+ */
+#define EM_NVM_PCIE_CTRL	0x1B
+#define EM_NVM_MSIX_N_MASK	(0x7 << EM_NVM_MSIX_N_SHIFT)
+#define EM_NVM_MSIX_N_SHIFT	7
 
 /*
  * Bus dma allocation structure used by
Index: sys/dev/e1000/if_em.c
===================================================================
--- sys/dev/e1000/if_em.c
+++ sys/dev/e1000/if_em.c
@@ -299,6 +299,8 @@
 static void	em_handle_rx(void *context, int pending);
 static void	em_handle_link(void *context, int pending);
 
+static void	em_enable_vectors_82574(struct adapter *);
+
 static void	em_set_sysctl_value(struct adapter *, const char *,
 		    const char *, int *, int);
 static int	em_set_flowcntl(SYSCTL_HANDLER_ARGS);
@@ -388,6 +390,12 @@
 SYSCTL_INT(_hw_em, OID_AUTO, enable_msix, CTLFLAG_RDTUN, &em_enable_msix, 0,
     "Enable MSI-X interrupts");
 
+#ifdef EM_MULTIQUEUE
+static int em_num_queues = 0;
+SYSCTL_INT(_hw_em, OID_AUTO, num_queues, CTLFLAG_RDTUN, &em_num_queues, 0,
+    "82574 only: Number of queues to configure, 0 indicates autoconfigure");
+#endif
+
 /* How many packets rxeof tries to clean at a time */
 static int em_rx_process_limit = 100;
 SYSCTL_INT(_hw_em, OID_AUTO, rx_process_limit, CTLFLAG_RDTUN,
@@ -458,6 +466,32 @@
 	return (ENXIO);
 }
 
+/*
+ * 82574 only:
+ * Write a new value to the EEPROM increasing the number of MSIX
+ * vectors from 3 to 5, for proper multiqueue support.
+ */
+static void
+em_enable_vectors_82574(struct adapter *adapter)
+{
+	struct e1000_hw *hw = &adapter->hw;
+	device_t dev = adapter->dev;
+	u16 edata;
+
+	e1000_read_nvm(hw, EM_NVM_PCIE_CTRL, 1, &edata);
+	printf("Current cap: %#06x\n", edata);
+	if (((edata & EM_NVM_MSIX_N_MASK) >> EM_NVM_MSIX_N_SHIFT) != 4
+	    && adapter->num_queues > 1) {
+		device_printf(dev, "Writing to eeprom: increasing "
+		    "reported MSIX vectors from 3 to 5...\n");
+		edata &= ~(EM_NVM_MSIX_N_MASK);
+		edata |= 4 << EM_NVM_MSIX_N_SHIFT;
+		e1000_write_nvm(hw, EM_NVM_PCIE_CTRL, 1, &edata);
+		e1000_update_nvm_checksum(hw);
+		device_printf(dev, "Writing to eeprom: done\n");
+	}
+}
+
 /*********************************************************************
  *  Device initialization routine
  *
@@ -550,6 +584,11 @@
 		goto err_pci;
 	}
 
+	/*
+	 * Setup MSI/X or MSI if PCI Express
+	 */
+	adapter->msix = em_setup_msix(adapter);
+
 	e1000_get_bus_info(hw);
 
 	/* Set up some sysctls for the tunable interrupt delays */
@@ -2437,14 +2476,6 @@
 	    rman_get_bushandle(adapter->memory);
 	adapter->hw.hw_addr = (u8 *)&adapter->osdep.mem_bus_space_handle;
 
-	/* Default to a single queue */
-	adapter->num_queues = 1;
-
-	/*
-	 * Setup MSI/X or MSI if PCI Express
-	 */
-	adapter->msix = em_setup_msix(adapter);
-
 	adapter->hw.back = &adapter->osdep;
 
 	return (0);
@@ -2701,14 +2732,19 @@
 	device_t dev = adapter->dev;
 	int val;
 
+	/* Nearly always going to use one queue */
+	adapter->num_queues = 1;
+
 	/*
-	** Setup MSI/X for Hartwell: tests have shown
-	** use of two queues to be unstable, and to
-	** provide no great gain anyway, so we simply
-	** seperate the interrupts and use a single queue.
+	** Try using MSI-X for Hartwell adapters
 	*/
 	if ((adapter->hw.mac.type == e1000_82574) &&
 	    (em_enable_msix == TRUE)) {
+#ifdef EM_MULTIQUEUE
+		adapter->num_queues = (em_num_queues == 1) ? 1 : 2;
+		if (adapter->num_queues > 1)
+			em_enable_vectors_82574(adapter);
+#endif
 		/* Map the MSIX BAR */
 		int rid = PCIR_BAR(EM_MSIX_BAR);
 		adapter->msix_mem = bus_alloc_resource_any(dev,
@@ -2720,16 +2756,31 @@
 			goto msi;
        		}
 		val = pci_msix_count(dev); 
-		/* We only need/want 3 vectors */
+
+#ifdef EM_MULTIQUEUE
+		/* We need 5 vectors in the multiqueue case */
+		if (adapter->num_queues == 2) {
+			if (val >= 5)
+				val = 5;
+			else {
+				adapter->num_queues = 1;
+				device_printf(adapter->dev,
+				    "Insufficient MSIX vectors for >1 queue, "
+				    "using single queue...\n");
+				goto msix_one;
+			}
+		} else
+#endif
+msix_one:
 		if (val >= 3)
 			val = 3;
 		else {
-               		device_printf(adapter->dev,
-			    "MSIX: insufficient vectors, using MSI\n");
+			device_printf(adapter->dev,
+			    "Insufficient MSIX vectors, using MSI\n");
 			goto msi;
 		}
 
-		if ((pci_alloc_msix(dev, &val) == 0) && (val == 3)) {
+		if ((pci_alloc_msix(dev, &val) == 0)) {
 			device_printf(adapter->dev,
 			    "Using MSIX interrupts "
 			    "with %d vectors\n", val);
@@ -2750,7 +2801,7 @@
 	}
        	val = 1;
        	if (pci_alloc_msi(dev, &val) == 0) {
-               	device_printf(adapter->dev,"Using an MSI interrupt\n");
+               	device_printf(adapter->dev, "Using an MSI interrupt\n");
 		return (val);
 	} 
 	/* Should only happen due to manual configuration */