From: Jeff Garzik <jeff@garzik.org>
To: Jeremy Higdon <jeremy@sgi.com>
Cc: "Dailey, Nate" <Nate.Dailey@stratus.com>, linux-ide@vger.kernel.org
Subject: Re: [PATCH 2.6.20] sata_vsc: use default cache line size if non-zero
Date: Thu, 15 Feb 2007 18:14:12 -0500 [thread overview]
Message-ID: <45D4E944.2090500@garzik.org> (raw)
In-Reply-To: <20070208085938.GA142057@sgi.com>
Jeremy Higdon wrote:
> On Wed, Feb 07, 2007 at 09:29:28AM -0500, Dailey, Nate wrote:
>> The attached patch modifies drivers/ata/sata_vsc.c to only set the cache
>> line size to 0x80 if the default value is zero. Apparently zero isn't
>> allowed due to a bug in the chip, but I've found performance is much
>> better with the (non-zero) default instead of 0x80.
>>
>> Signed-off-by: Nate Dailey <nate.dailey@stratus.com>
> Signed-off-by: Jeremy Higdon <jeremy@sgi.com>
>
> Here is the attachment from Nate, inline.
>
> Content-Description: sata_vsc_CLS.patch
> --- old/drivers/ata/sata_vsc.c 2007-02-04 13:44:54.000000000 -0500
> +++ new/drivers/ata/sata_vsc.c 2007-02-07 09:13:17.000000000 -0500
> @@ -345,6 +345,7 @@ static int __devinit vsc_sata_init_one (
> int pci_dev_busy = 0;
> void __iomem *mmio_base;
> int rc;
> + u8 cls;
>
> if (!printed_version++)
> dev_printk(KERN_DEBUG, &pdev->dev, "version " DRV_VERSION "\n");
> @@ -394,9 +395,13 @@ static int __devinit vsc_sata_init_one (
> base = (unsigned long) mmio_base;
>
> /*
> - * Due to a bug in the chip, the default cache line size can't be used
> + * Due to a bug in the chip, the default cache line size can't be
> + * used (unless the default is non-zero).
> */
> - pci_write_config_byte(pdev, PCI_CACHE_LINE_SIZE, 0x80);
> + pci_read_config_byte(pdev, PCI_CACHE_LINE_SIZE, &cls);
> + if (cls == 0x00) {
> + pci_write_config_byte(pdev, PCI_CACHE_LINE_SIZE, 0x80);
> + }
applied, after removing the superfluous braces :)
prev parent reply other threads:[~2007-02-15 23:14 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-02-07 14:29 [PATCH 2.6.20] sata_vsc: use default cache line size if non-zero Dailey, Nate
2007-02-08 8:59 ` Jeremy Higdon
2007-02-15 23:14 ` Jeff Garzik [this message]
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