From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jeff Garzik <jeff@garzik.org>
Subject: Re: 2.6.29-rc libata sff 32bit PIO regression
Date: Mon, 02 Feb 2009 23:00:40 -0500
Message-ID: <4987C168.5060807@garzik.org>
References: <Pine.LNX.4.64.0901211322010.15945@blonde.anvils> <20090126191256.04dfb6d3@lxorguk.ukuu.org.uk>
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To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Hugh Dickins <hugh@veritas.com>, Jeff Garzik <jgarzik@redhat.com>, "Rafael J. Wysocki" <rjw@sisk.pl>, linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org

Alan Cox wrote:
> And while we are at it fix the 32bit PIO handling for VLB for this case
> too
> 
> pata_legacy: For VLB 32bit PIO don't try tricks with slop
> 
> From: Alan Cox <alan@lxorguk.ukuu.org.uk>
> 
> These devices are generally used with ATA anyway and it seems that some
> ATAPI will need us to issue the right number of words. Therefore as we
> can't switch mid burst on VLB devices we should only use 32bit I/O for
> suitable block sizes.
> ---
> 
>  drivers/ata/pata_legacy.c |    7 ++++---
>  1 files changed, 4 insertions(+), 3 deletions(-)
> 
> 
> diff --git a/drivers/ata/pata_legacy.c b/drivers/ata/pata_legacy.c
> index 6c1d778..e3bc1b4 100644
> --- a/drivers/ata/pata_legacy.c
> +++ b/drivers/ata/pata_legacy.c
> @@ -283,9 +283,10 @@ static void pdc20230_set_piomode(struct ata_port *ap, struct ata_device *adev)
>  static unsigned int pdc_data_xfer_vlb(struct ata_device *dev,
>  			unsigned char *buf, unsigned int buflen, int rw)
>  {
> -	if (ata_id_has_dword_io(dev->id)) {
> +	int slop = buflen & 3;
> +	/* 32bit I/O capable *and* we need to write a whole number of dwords */
> +	if (ata_id_has_dword_io(dev->id) && (slop == 0 || slop == 3)) {
>  		struct ata_port *ap = dev->link->ap;
> -		int slop = buflen & 3;
>  		unsigned long flags;
>  
>  		local_irq_save(flags);
> @@ -735,7 +736,7 @@ static unsigned int vlb32_data_xfer(struct ata_device *adev, unsigned char *buf,
>  	struct ata_port *ap = adev->link->ap;
>  	int slop = buflen & 3;
>  
> -	if (ata_id_has_dword_io(adev->id)) {
> +	if (ata_id_has_dword_io(adev->id) && (slop == 0 || slop == 3)) {
>  		if (rw == WRITE)
>  			iowrite32_rep(ap->ioaddr.data_addr, buf, buflen >> 2);

tested etc.?  I don't see a sign-off...