Hi Nicholas, Thanks for your help. Replies follow below. Kind Regards, Luís On Sun, Mar 8, 2020 at 5:51 AM Nicholas Johnson <nicholas.johnson-opensource@xxxxxxxxxxxxxx> wrote: > > Hi, > > > On Sat, Mar 7, 2020 at 12:11 PM Luís Mendes <luis.p.mendes@xxxxxxxxx> wrote: > > > > This issue seems to happen only with the Coral Edge TPU device, but it > > > > happens independently of whether the gasket/apex driver module is > > > > loaded or not. The BAR 0 of the Coral device is not assigned either > > > > way. > > > > > > > > Luís > > So the problem only occurs with the Coral Edge TPU device, so there is a > possibility that it is not a problem with the platform, or something > caused by the combination of the TPU and platform. Is it possible to put > the TPU into an X86 system with the same kernel version(s) to add more > evidence to this theory? If it works on X86 then we can focus on the > differences between X86 and ARM. I've tested two Coral TPUs on two x86_64 platforms and the BARs seem to be assigned, however the driver fails to load, during probe and the system is unable to shutdown cleanly, but I think that is a driver issue when setting up sysfs entries. I can blacklist gasket/apex, if it helps in some way, or try an older kernel. Dmesg log for one of the x86_64 system is here: https://pastebin.ubuntu.com/p/FHhHNN6XTF/ lspci -vvv for the same x86_64 system is here: https://pastebin.ubuntu.com/p/xbSNWFQ9TS/ > > Also, please revert c13704f5685d "PCI: Avoid double hpmemsize MMIO > window assignment" or try with Linux v5.4 which does not have this > commit, just to rule out the possibility of it causing issues. This > patch helps me and also solved the problem of one other person using an > ARM computer who came to us regarding a problem. However, it could also > adversely affect unknown use cases - it is impossible to completely rule > out, due to the nature of how drivers/pci/setup-bus.c is written. On armhf with 5.4.14 the problem remains, BAR 0 and BAR 2 are not assigned: https://pastebin.ubuntu.com/p/9H2qqqMNJN/ I've also tried kernel 4.20.11 and the problem also exists. I've got JTAG on this system with OpenOCD. I believe I can debug the kernel, if needed. > > Kind regards, > Nicholas
