On Tue, Jan 02, 2018 at 01:02:15PM -0600, Bjorn Helgaas wrote: > On Fri, Dec 29, 2017 at 12:54:15PM +0530, Oza Pawandeep wrote: > > This patch set brings in support for DPC and AER to co-exist and not to > > race for recovery. > > > > The current implementation of AER and error message broadcasting to the > > EP driver is tightly coupled and limited to AER service driver. > > It is important to factor out broadcasting and other link handling > > callbacks. So that not only when AER gets triggered, but also when DPC get > > triggered, or both get triggered simultaneously (for e.g. ERR_FATAL), > > callbacks are handled appropriately. > > having modularized the code, the race between AER and DPC is handled > > gracefully. > > for e.g. when DPC is active and kicked in, AER should not attempt to do > > recovery, because DPC takes care of it. > > High-level question: > > We have some convoluted code in negotiate_os_control() and > aer_service_init() that (I think) essentially disables AER unless the > platform firmware grants us permission to use it. > > The last implementation note in PCIe r3.1, sec 6.2.10 says > > DPC may be controlled in some configurations by platform firmware > and in other configurations by the operating system. DPC > functionality is strongly linked with the functionality in Advanced > Error Reporting. To avoid conflicts over whether platform firmware > or the operating system have control of DPC, it is recommended that > platform firmware and operating systems always link the control of > DPC to the control of Advanced Error Reporting. > > I read that as suggesting that we should enable DPC support in Linux > if and only if we also enable AER. But I don't see anything in DPC > that looks like that. Should there be something there? Should DPC be > restructured so it's enabled and handled inside the AER driver instead > of being a separate driver? Yes, I agree the two should be linked. I submitted a patch for that here, though driver responsibilities are still separate in this series: https://marc.info/?l=linux-pci&m=151371742225111&w=2
