[PATCH] ahci: Ensure that we don't grab both functions

When we force the chip into dual fn mode so we get PATA and AHCI we must
be sure we don't then do anything dumb like try and grab both with the AHCI
driver.

Signed-off-by: Alan Cox <[e-mail]>
Signed-off-by: Jeff Garzik <[e-mail]>

drivers/scsi/ahci.c

···
 	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;
···
 
 	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);