Re: [PATCH 2.6.34] r8169: enable 64-bit DMA by default for PCIExpress devices (v2)

[David Miller]

From: Robert Hancock <hancockrwd@xxxxxxxxx>
Date: Fri, 19 Feb 2010 19:00:46 -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>

Applied, thanks Robert.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/