Improve the MSIX setup code in the drivers, thanks to Marius for

the changes. Make sure that pci_alloc_msix() does give us the vectors
we need and fall back to MSI when it doesn't, also release any that
were allocated when insufficient.

MFC after: 3 days

1 files changed, 14 insertions, 7 deletions

diff --git a/sys/dev/e1000/if_em.c b/sys/dev/e1000/if_em.c
index 9499953..b3327e8 100644
--- a/sys/dev/e1000/if_em.c
+++ b/sys/dev/e1000/if_em.c
@@ -2277,7 +2277,7 @@ em_local_timer(void *arg)
 
 	/* Mask to use in the irq trigger */
 	if (adapter->msix_mem)
-		trigger = rxr->ims; /* RX for 82574 */
+		trigger = rxr->ims;
 	else
 		trigger = E1000_ICS_RXDMT0;
 
@@ -2775,23 +2775,30 @@ em_setup_msix(struct adapter *adapter)
 		if (val >= 3)
 			val = 3;
 		else {
-			bus_release_resource(dev, SYS_RES_MEMORY,
-			    PCIR_BAR(EM_MSIX_BAR), adapter->msix_mem);
-			adapter->msix_mem = NULL;
                		device_printf(adapter->dev,
-			    "MSIX: incorrect vectors, using MSI\n");
+			    "MSIX: insufficient vectors, using MSI\n");
 			goto msi;
 		}
 
-		if (pci_alloc_msix(dev, &val) == 0) {
+		if ((pci_alloc_msix(dev, &val) == 0) && (val == 3)) {
 			device_printf(adapter->dev,
 			    "Using MSIX interrupts "
 			    "with %d vectors\n", val);
 			return (val);
 		}
-		/* Fall through to MSI */
+
+		/*
+		** If MSIX alloc failed or provided us with
+		** less than needed, free and fall through to MSI
+		*/
+		pci_release_msi(dev);
 	}
 msi:
+	if (adapter->msix_mem != NULL) {
+		bus_release_resource(dev, SYS_RES_MEMORY,
+		    PCIR_BAR(EM_MSIX_BAR), adapter->msix_mem);
+		adapter->msix_mem = NULL;
+	}
        	val = 1;
        	if (pci_alloc_msi(dev, &val) == 0) {
                	device_printf(adapter->dev,"Using an MSI interrupt\n");