I have looked at their webpage and I see no signs of a firmware that can be downloaded. https://coral.ai/products/pcie-accelerator If it is acceptable for you I'll provide a patch for such a quirk. Thanks, Luís On Thu, Apr 9, 2020 at 5:30 PM Bjorn Helgaas <helgaas@xxxxxxxxxx> wrote: > > On Thu, Apr 09, 2020 at 04:25:40PM +0100, Luís Mendes wrote: > > Hi Bjorn, > > > > I've good news. I've found the culprit and it is a pretty simple > > issue, however the good solution is not obvious to me. > > Can you help in finding the best way to patch this issue? > > > > So first detailing the problem in file setup_bus.c there is this *if > > condition* to ignore resources from classless devices and so > > it is that this Google/Coral Edge TPU is a classless device with class 0xff: > > > > static void __dev_sort_resources(struct pci_dev *dev, struct list_head *head) > > { > > u16 class = dev->class >> 8; > > > > pci_info(dev, "%s\n", __func__); > > /* Don't touch classless devices or host bridges or IOAPICs */ > > if (class == PCI_CLASS_NOT_DEFINED || class == PCI_CLASS_BRIDGE_HOST) > > return; > > .... > > > > So the one possible trivial, non generic, attempt that works is to do: > > static void __dev_sort_resources(struct pci_dev *dev, struct list_head *head) > > { > > u16 class = dev->class >> 8; > > > > pci_info(dev, "%s\n", __func__); > > /* Don't touch classless devices or host bridges or IOAPICs */ > > if ((class == PCI_CLASS_NOT_DEFINED && !(dev->vendor == 0x1ac1 && > > dev->device==0x089a)) || class == PCI_CLASS_BRIDGE_HOST) > > return; > > .... > > > > What is your suggestion to make the solution generic? Create a > > whitelist? Remove this verification? I have no idea... nothing sounds > > good to me... > > Good detective work, thanks for chasing this down! > > I should have seen that check when adding the debug. Guess I thought > "sort", hmmm, that just re-orders things without actually changing the > content. But pdev_sort_resources() in fact *adds* resources to a > list, and if resources aren't on the list, we apparently don't assign > space for them. > > In any event, I would first check to see if there's an Edge TPU > firmware update that might set the class code. > > If not, we should probably add a quirk to override the class code, > similar to quirk_eisa_bridge(), fixup_rev1_53c810(), > fixup_ti816x_class(), quirk_tw686x_class(). > > Bjorn
