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Message-ID: <467CBC0C.6030001@gmail.com>
Date: Sat, 23 Jun 2007 15:22:04 +0900
From: Tejun Heo <htejun@gmail.com>
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To: Carlo Wood <carlo@alinoe.com>, Jeff Garzik <jeff@garzik.org>,
       Tejun Heo <htejun@gmail.com>, Manoj Kasichainula <manoj@io.com>,
       linux-kernel@vger.kernel.org
Subject: Re: SATA RAID5 speed drop of 100 MB/s
References: <20070620224847.GA5488@alinoe.com> <4679B2DE.9090903@garzik.org> <20070622214410.GB6970@alinoe.com> <20070623035451.GA5522@alinoe.com>
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Carlo Wood wrote:
> For what it's worth... I tried applying
> 
> --- a/drivers/ata/ahci.c
> +++ b/drivers/ata/ahci.c
> @@ -516,6 +516,8 @@ static void ahci_save_initial_config(struct pci_dev *pdev,
>          * reset.  Values without are used for driver operation.
>          */
>         hpriv->saved_cap = cap = readl(mmio + HOST_CAP);
> +       hpriv->saved_cap &= ( (1<<28) | (1<<17) );
> +       hpriv->saved_cap |= (1 << 27);
>         hpriv->saved_port_map = port_map = readl(mmio + HOST_PORTS_IMPL);

Hmmm... That's super-odd.  You win my oddest-of-the-month award.  :-)

I'll think about it a bit.  Please stand by.

-- 
tejun