Re: [git patch] libata bug fix

[Andrew Morton <akpm@linux-foundation.org>]

On Wed, 24 Feb 2010 22:49:37 -0500 Jeff Garzik <jeff@garzik.org> wrote:

> 
> This is a fix that probably should have gone into 2.6.33.

It still can if we cc stable@kernel.org?

>  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;