r8169: enable 64-bit DMA by default for PCI Express devices (v2)
r8169: enable 64-bit DMA by default for PCI Express devices (v2)

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 <6cfcd53195f1aa0ac67c127c865c06914056063f@gmail.com>
Signed-off-by: David S. Miller <fe08d3c717adf2ae63592e4c9aec6e3e404d8e3e@davemloft.net>

KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs