On 9/27/2020 10:43 PM, Kuppuswamy, Sathyanarayanan wrote:
> FATAL + no-hotplug - In this case, link will still be reseted. But
> currently driver state is not properly restored. So I attempted
> to restore it using pci_reset_bus().
>
> status = reset_link(dev);
> - if (status != PCI_ERS_RESULT_RECOVERED) {
> + if (status == PCI_ERS_RESULT_RECOVERED) {
> + status = PCI_ERS_RESULT_NEED_RESET;
>
> ...
>
> if (status == PCI_ERS_RESULT_NEED_RESET) {
> /*
> - * TODO: Should call platform-specific
> - * functions to reset slot before calling
> - * drivers' slot_reset callbacks?
> + * TODO: Optimize the call to pci_reset_bus()
> + *
> + * There are two components to pci_reset_bus().
> + *
> + * 1. Do platform specific slot/bus reset.
> + * 2. Save/Restore all devices in the bus.
> + *
> + * For hotplug capable devices and fatal errors,
> + * device is already in reset state due to link
> + * reset. So repeating platform specific slot/bus
> + * reset via pci_reset_bus() call is redundant. So
> + * can optimize this logic and conditionally call
> + * pci_reset_bus().
> */
> + pci_reset_bus(dev);
I think we have to go to remove/rescan for this case as you also
mentioned above. There is no state to save. All BAR assignments
are gone. Entire device programming is also lost.
I don't think pci_reset_bus() can recover from this situation safely.
It will make things worse by saving/restoring the hardware default
state.
This should remove/rescan logic should be inside DPC's slot_reset()
function BTW. Not here.
