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All PCI devices are "safe" for P2P by spec. I've never heard of a non-complaint device causing problems in this area. The issue is always SOC support inside the CPU and that is delt with inside the P2P subsystem logic. If we ever see a problem it would be delt with by quirking the broken device through pci-quirks and having the p2p subsystem refuse any p2p with that device. Jason