Merge branch 'upstream-linus' of master.kernel.org:/pub/scm/linux/kernel/git/jgarzik...

[sfrench/cifs-2.6.git] / drivers / ata / libata-sff.c

diff --git a/drivers/ata/libata-sff.c b/drivers/ata/libata-sff.c
index 6c289c7b13224119d2ff13756ad556bcbff11fcf..8023167bbbeb68623fd9939887010fb74362cb70 100644 (file)
--- a/drivers/ata/libata-sff.c
+++ b/drivers/ata/libata-sff.c
@@ -297,7 +297,7 @@ void ata_bmdma_start (struct ata_queued_cmd *qc)
        dmactl = ioread8(ap->ioaddr.bmdma_addr + ATA_DMA_CMD);
        iowrite8(dmactl | ATA_DMA_START, ap->ioaddr.bmdma_addr + ATA_DMA_CMD);
 
-       /* Strictly, one may wish to issue a readb() here, to
+       /* Strictly, one may wish to issue an ioread8() here, to
         * flush the mmio write.  However, control also passes
         * to the hardware at this point, and it will interrupt
         * us when we are to resume control.  So, in effect,
@@ -307,6 +307,9 @@ void ata_bmdma_start (struct ata_queued_cmd *qc)
         * is expected, so I think it is best to not add a readb()
         * without first all the MMIO ATA cards/mobos.
         * Or maybe I'm just being paranoid.
+        *
+        * FIXME: The posting of this write means I/O starts are
+        * unneccessarily delayed for MMIO
         */
 }
 
@@ -573,6 +576,10 @@ 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)