diff --git a/drivers/scsi/ahci.c b/drivers/scsi/ahci.c
index 7447ba0374e8..77e7202a0eba 100644
--- a/drivers/scsi/ahci.c
+++ b/drivers/scsi/ahci.c
@@ -1323,6 +1323,17 @@ static int ahci_init_one (struct pci_dev *pdev, const struct pci_device_id *ent)
 	if (!printed_version++)
 		dev_printk(KERN_DEBUG, &pdev->dev, "version " DRV_VERSION "\n");
 
+	/* JMicron-specific fixup: make sure we're in AHCI mode */
+	/* This is protected from races with ata_jmicron by the pci probe
+	   locking */
+	if (pdev->vendor == PCI_VENDOR_ID_JMICRON) {
+		/* AHCI enable, AHCI on function 0 */
+		pci_write_config_byte(pdev, 0x41, 0xa1);
+		/* Function 1 is the PATA controller */
+		if (PCI_FUNC(pdev->devfn))
+			return -ENODEV;
+	}
+
 	rc = pci_enable_device(pdev);
 	if (rc)
 		return rc;
@@ -1378,10 +1389,6 @@ static int ahci_init_one (struct pci_dev *pdev, const struct pci_device_id *ent)
 	if (have_msi)
 		hpriv->flags |= AHCI_FLAG_MSI;
 
-	/* JMicron-specific fixup: make sure we're in AHCI mode */
-	if (pdev->vendor == 0x197b)
-		pci_write_config_byte(pdev, 0x41, 0xa1);
-
 	/* initialize adapter */
 	rc = ahci_host_init(probe_ent);
 	if (rc)