atl1: disable broken 64-bit DMA

64-bit DMA causes data corruption with atl1.  We don't know why, and Atheros
is working on it.  For now, just use 32-bit DMA.  This is a big hack that is
probably wrong, but it stops the bleeding.
Signed-off-by: Luca Tettamanti <kronos.it@gmail.com>
Acked-by: Chris Snook <csnook@redhat.com>
Acked-by: Jay Cliburn <jacliburn@bellsouth.net>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

drivers/net/atl1/atl1_main.c

@@ -2203,22 +2203,21 @@ static int __devinit atl1_probe(struct pci_dev *pdev,
 	struct net_device *netdev;
 	struct atl1_adapter *adapter;
 	static int cards_found = 0;
-	bool pci_using_64 = true;
 	int err;
 
 	err = pci_enable_device(pdev);
 	if (err)
 		return err;
 
-	err = pci_set_dma_mask(pdev, DMA_64BIT_MASK);
-	if (err) {
+	/*
+	 * 64-bit DMA currently has data corruption problems, so let's just
+	 * use 32-bit DMA for now.  This is a big hack that is probably wrong.
+	 */
 	err = pci_set_dma_mask(pdev, DMA_32BIT_MASK);
 	if (err) {
 		dev_err(&pdev->dev, "no usable DMA configuration\n");
 		goto err_dma;
 	}
-		pci_using_64 = false;
-	}
 	/* Mark all PCI regions associated with PCI device
 	 * pdev as being reserved by owner atl1_driver_name
 	 */
@@ -2282,7 +2281,6 @@ static int __devinit atl1_probe(struct pci_dev *pdev,
 
 	netdev->ethtool_ops = &atl1_ethtool_ops;
 	adapter->bd_number = cards_found;
-	adapter->pci_using_64 = pci_using_64;
 
 	/* setup the private structure */
 	err = atl1_sw_init(adapter);
@@ -2299,9 +2297,6 @@ static int __devinit atl1_probe(struct pci_dev *pdev,
 	 */
 	/* netdev->features |= NETIF_F_TSO; */
 
-	if (pci_using_64)
-		netdev->features |= NETIF_F_HIGHDMA;
-
 	netdev->features |= NETIF_F_LLTX;
 
 	/*