[+cc Austin] On Thu, Dec 26, 2019 at 04:39:11PM -0800, sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx wrote: > From: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx> > > As per PCI firmware specification r3.2 System Firmware Intermediary > (SFI) _OSC and DPC Updates ECR > (https://members.pcisig.com/wg/PCI-SIG/document/13563), What is the state of this ECR? I see it in the "PCI Express Review Zone Archive". I don't know what the usage is of the "Review Zone" vs the "Review Zone Archive / PCI Express Review Zone Archive". AFAICS, it is not listed in any of the "Documents for 60 Day Member Review". And I think it needs some clarification (for one thing, it needs to say what the red/blue text means). I've mentioned some other items to Austin, but I haven't read it in detail because it seems like it's not quite baked yet. E.g., there's language about "it may make sense for an embedded system OS to own SFI, but it's recommended that general-purpose OSes never request SFI ownership." That's useless: Linux is certainly a general purpose OS, but Linux is also often an embedded OS. So the ECR doesn't provide useful guidance about how an OS should decide whether to request SFI ownership. Making code changes based on a published spec or ECN is fine, obviously. Changes based on an ECR that is well on track to being accepted, e.g., is in the 60-day review period, are probably OK. I don't yet have warm fuzzies about this ECR because I have no idea how far along it is. We might be able to justify some of these changes based on other specs; it just sounds weird to me to say "based on this Engineering Change Request that might be accepted someday, we must do X". Anybody can dream up an ECR that says anything at all, so AFAICT, an ECR is not at all authoritative. > sec titled > "DPC Event Handling Implementation Note", page 10, Error Disconnect > Recover (EDR) support allows OS to handle error recovery and clearing > Error Registers even in FF mode. So create exception for FF mode checks > in pci_cleanup_aer_uncorrect_error_status(), pci_aer_clear_fatal_status() > and pci_cleanup_aer_error_status_regs() functions when its being called > from DPC code path.
