Commit 453d3131 authored by Robert Hancock's avatar Robert Hancock Committed by Jeff Garzik
Browse files

ahci: disable FPDMA auto-activate optimization on NVIDIA AHCI

Mike Cui reported that his system with an NVIDIA MCP79 (aka MCP7A)
chipset stopped working with 2.6.32. The problem appears to be that
2.6.32 now enables the FPDMA auto-activate optimization in the ahci
driver. The drive works fine with this enabled on an Intel AHCI so
this appears to be a chipset bug.  Since MCP79 is a fairly recent
NVIDIA chipset and we don't have any info on whether any other NVIDIA
chipsets have this issue, disable FPDMA AA optimization on all NVIDIA
AHCI controllers for now.

Should address

Signed-off-by: default avatarRobert Hancock <>
While-we-investigate-issue-this-patch-looks-good-to-me-by: default avatarPrajakta Gudadhe <>
Signed-off-by: default avatarJeff Garzik <>
parent 60b341b7
......@@ -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)
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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