[PATCH] libata:pata_atiixp: Don't use unconnected secondary port on SB600

[Darren Stevens <darren@xxxxxxxxxxxxxxxx>]

    The AMD SB600 southbridge has an PATA IDE interface, but the
    secondary port has no physical connections, so is disabled in
    the PCI header which makes it appear as a legacy port.
    
    On most systems this causes no trouble, but the Amigaone X1000 has
    an SB600 connected to a PowerPC SoC PCI-e root port, with an
    emulated ISA bus. On this system a kernel panic occurs at boot
    time during device attach for the secondary port.
    
    Mark the port as 'dummy' to prevent this. As a bonus, disabling
    this will slightly speed up booting on PC systems using an
    SB600 as they will now skip 2 known empty ports.
    
    Signed-off-by: Darren Stevens <Darren@xxxxxxxxxxxxxxxx>

---

diff --git a/drivers/ata/pata_atiixp.c b/drivers/ata/pata_atiixp.c
index 49d705c..4d49fd3 100644
--- a/drivers/ata/pata_atiixp.c
+++ b/drivers/ata/pata_atiixp.c
@@ -278,6 +278,10 @@ static int atiixp_init_one(struct pci_dev *pdev, const struct pci_device_id *id)
 	};
 	const struct ata_port_info *ppi[] = { &info, &info };
 
+	/* SB600 doesn't have secondary port wired */
+	if((pdev->device == PCI_DEVICE_ID_ATI_IXP600_IDE))
+		ppi[1] = &ata_dummy_port_info;
+
 	return ata_pci_bmdma_init_one(pdev, ppi, &atiixp_sht, NULL,
 				      ATA_HOST_PARALLEL_SCAN);
 }