Hi, I have a question about this patch from the web link (https://lwn.net/ml/linux-kernel/[email protected]/). According to the PCIe spec (PCIe 3.0), ACS Upstream Forwarding (UF) seems quite similar with Request Redirect (RR). Why pci_quirk_disable_intel_spt_pch_acs_redir in this patch seems disable RR but not UF?
One related question in further: what's the difference between UF and RR (examples preferred)? Both seems redirect traffics originated from downstreams. Especially I feel confused about UF in the PCIe spec: PCIe switches must always route upstream requests towards RC because they target upstream destinations, why these switches need UF config? Thanks!
