diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
index 54f38c21dd9..ef5e6b6e6e6 100644
--- a/drivers/ata/ahci.c
+++ b/drivers/ata/ahci.c
@@ -1036,6 +1036,7 @@ static int ahci_deinit_port(struct ata_port *ap, const char **emsg)
 static int ahci_reset_controller(struct ata_host *host)
 {
 	struct pci_dev *pdev = to_pci_dev(host->dev);
+	struct ahci_host_priv *hpriv = host->private_data;
 	void __iomem *mmio = host->iomap[AHCI_PCI_BAR];
 	u32 tmp;
 
@@ -1078,8 +1079,10 @@ static int ahci_reset_controller(struct ata_host *host)
 
 		/* configure PCS */
 		pci_read_config_word(pdev, 0x92, &tmp16);
-		tmp16 |= 0xf;
-		pci_write_config_word(pdev, 0x92, tmp16);
+		if ((tmp16 & hpriv->port_map) != hpriv->port_map) {
+			tmp16 |= hpriv->port_map;
+			pci_write_config_word(pdev, 0x92, tmp16);
+		}
 	}
 
 	return 0;