libata-sff; Unbreak non DMA capable controllers again

Seems nobody else is checking/testing this case as it keeps getting
horked.

If we have no BAR4 mapping on an SFF controller this is *NOT* an error,
it just means it isn't doing BMDMA.

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

1 files changed, 4 insertions, 0 deletions

diff --git a/drivers/ata/libata-sff.c b/drivers/ata/libata-sff.c
index 6c289c7b1322..1cce2198baaf 100644
--- a/drivers/ata/libata-sff.c
+++ b/drivers/ata/libata-sff.c
@@ -573,6 +573,10 @@ int ata_pci_init_bmdma(struct ata_host *host)
         struct pci_dev *pdev = to_pci_dev(gdev);
         int i, rc;
 
+        /* No BAR4 allocation: No DMA */
+        if (pci_resource_start(pdev, 4) == 0)
+                return 0;
+
         /* TODO: If we get no DMA mask we should fall back to PIO */
         rc = pci_set_dma_mask(pdev, ATA_DMA_MASK);
         if (rc)