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.
From ARM64 maintainer's viewpoint:
http:// marc.info/ ?l=linux- arm-kernel& m=1417088384044 70&w=2
Either way, I don't think it's a problem for the kernel. We just need to
non-coherent ops for a coherent device is not safe as the CPU can
change the default DMA ops to coherent when booting with ACPI (using
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,