Comment 3 for bug 1386490

From ARM64 maintainer's viewpoint:

         http://marc.info/?l=linux-arm-kernel&m=141708838404470&w=2

         Either way, I don't think it's a problem for the kernel. We just need to
         change the default DMA ops to coherent when booting with ACPI (using
         non-coherent ops for a coherent device is not safe as the CPU can
         corrupt cache lines written by the device).

So I suggest to revert c7a4a7658d689f6 for utopic since utopic ships APM's
non-upstreamed PCI implementation, and APM's ARM64 Soc is coherent
arch.

Dann, what do you think about it?

Thanks,