Re: [PATCH] ahci: disable FPDMA auto-activate optimization on NVIDIA AHCI

[Robert Hancock <hancockrwd@gmail.com>]

Hi Mike, have you had a chance to try out this patch yet?

On Tue, Jan 26, 2010 at 10:33 PM, Robert Hancock <hancockrwd@gmail.com> wrote:
> 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 http://bugzilla.kernel.org/show_bug.cgi?id=14922
>
> Signed-off-by: Robert Hancock <hancockrwd@gmail.com>
>
> ---
>
> Mike, can you test this out and make sure this resolves the problem for you?
>
> diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
> index b8bea10..47e57dc 100644
> --- a/drivers/ata/ahci.c
> +++ b/drivers/ata/ahci.c
> @@ -3067,8 +3067,16 @@ 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;
>