Hello, On Thu, 29 Oct 2020 14:30:22 -0500 Bjorn Helgaas <helgaas@xxxxxxxxxx> wrote: > We could quirk these NICs to avoid the retrain, but since aardvark and > mvebu have no obvious connection and WLE200/WLE900 and MT76 have no > obvious connection, I doubt there's a simple hardware defect that > explains all these. aardvark and mvebu have one very strong connection: they are the only two drivers making use of the PCI Bridge emulation logic in drivers/pci/pci-bridge-emul.c: drivers/pci$ git grep pci-bridge-emul akefile:obj-$(CONFIG_PCI_BRIDGE_EMUL) += pci-bridge-emul.o controller/pci-aardvark.c:#include "../pci-bridge-emul.h" controller/pci-mvebu.c:#include "../pci-bridge-emul.h" pci-bridge-emul.c:#include "pci-bridge-emul.h" I haven't read the whole thread, but it is important to keep in mind that on those two platforms, the PCI Bridge seen by Linux is *not* a real HW bridge. It is faked by the the pci-bridge-emul code. So if this code has defects/bugs in how it emulates a PCI Bridge behavior, you might see weird things. Best regards, Thomas -- Thomas Petazzoni, CTO, Bootlin Embedded Linux and Kernel engineering https://bootlin.com
