[git patch] libata bug fix

[Jeff Garzik]

This is a fix that probably should have gone into 2.6.33.  It never
received an ack from the bug reporter, hence the delay,
but NVIDIA ok'd it anyway.  It merely disables an optimization.




Please pull from 'upstream-linus' branch of
master.kernel.org:/pub/scm/linux/kernel/git/jgarzik/libata-dev.git upstream-linus

to receive the following updates:

 drivers/ata/ahci.c |   12 ++++++++++--
 1 files changed, 10 insertions(+), 2 deletions(-)

Robert Hancock (1):
      ahci: disable FPDMA auto-activate optimization on NVIDIA AHCI

diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
index b343903..a6a736a 100644
--- a/drivers/ata/ahci.c
+++ b/drivers/ata/ahci.c
@@ -3082,8 +3082,16 @@ static int ahci_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
 	ahci_save_initial_config(pdev, hpriv);
 
 	/* prepare host */
-	if (hpriv->cap & HOST_CAP_NCQ)
-		pi.flags |= ATA_FLAG_NCQ | ATA_FLAG_FPDMA_AA;
+	if (hpriv->cap & HOST_CAP_NCQ) {
+		pi.flags |= ATA_FLAG_NCQ;
+		/* Auto-activate optimization is supposed to be supported on
+		   all AHCI controllers indicating NCQ support, but it seems
+		   to be broken at least on some NVIDIA MCP79 chipsets.
+		   Until we get info on which NVIDIA chipsets don't have this
+		   issue, if any, disable AA on all NVIDIA AHCIs. */
+		if (pdev->vendor != PCI_VENDOR_ID_NVIDIA)
+			pi.flags |= ATA_FLAG_FPDMA_AA;
+	}
 
 	if (hpriv->cap & HOST_CAP_PMP)
 		pi.flags |= ATA_FLAG_PMP;
--
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