Re: [PATCH 2.6.34] r8169: enable 64-bit DMA by default for PCIExpress devices

[David Miller]

From: Robert Hancock <hancockrwd@xxxxxxxxx>
Date: Wed, 17 Feb 2010 21:06:41 -0600

> Currently use of 64-bit DMA is disabled in r8169 unless the user passes the
> use_dac module option. This is reasonable for conventional PCI devices where
> broken chipsets may not handle dual-address-cycle transfers properly for
> 32-bit slots and so this may not be safe. However, PCI Express should not have
> this problem and not using 64-bit DMA results in DMA transfers needlessly using
> the IOMMU or SWIOTLB. Set the use_dac module parameter to a new default value of
> -1 which results in 64-bit DMA being enabled by default for PCI Express devices
> only.
> 
> Signed-off-by: Robert Hancock <hancockrwd@xxxxxxxxx>

This patch is fine, but it doesn't apply cleanly to net-next-2.6

Please fix this up and resubmit, thanks!
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