1 files changed, 5 insertions, 6 deletions

diff --git a/drivers/ata/pata_serverworks.c b/drivers/ata/pata_serverworks.c
index df68806df4be..8bed88873720 100644
--- a/drivers/ata/pata_serverworks.c
+++ b/drivers/ata/pata_serverworks.c
@@ -274,28 +274,27 @@ static void serverworks_set_dmamode(struct ata_port *ap, struct ata_device *adev
 {
         static const u8 dma_mode[] = { 0x77, 0x21, 0x20 };
         int offset = 1 + 2 * ap->port_no - adev->devno;
-        int devbits = (2 * ap->port_no + adev->devno);
+        int devbits = 2 * ap->port_no + adev->devno;
         u8 ultra;
         u8 ultra_cfg;
         struct pci_dev *pdev = to_pci_dev(ap->host->dev);
 
         pci_read_config_byte(pdev, 0x54, &ultra_cfg);
+        pci_read_config_byte(pdev, 0x56 + ap->port_no, &ultra);
+        ultra &= ~(0x0F << (adev->devno * 4));
 
         if (adev->dma_mode >= XFER_UDMA_0) {
                 pci_write_config_byte(pdev, 0x44 + offset,  0x20);
 
-                pci_read_config_byte(pdev, 0x56 + ap->port_no, &ultra);
-                ultra &= ~(0x0F << (ap->port_no * 4));
                 ultra |= (adev->dma_mode - XFER_UDMA_0)
-                                        << (ap->port_no * 4);
-                pci_write_config_byte(pdev, 0x56 + ap->port_no, ultra);
-
+                                        << (adev->devno * 4);
                 ultra_cfg |=  (1 << devbits);
         } else {
                 pci_write_config_byte(pdev, 0x44 + offset,
                         dma_mode[adev->dma_mode - XFER_MW_DMA_0]);
                 ultra_cfg &= ~(1 << devbits);
         }
+        pci_write_config_byte(pdev, 0x56 + ap->port_no, ultra);
         pci_write_config_byte(pdev, 0x54, ultra_cfg);
 }