Re: [PATCH v18 03/11] PCI/DPC: Fix DPC recovery issue in non hotplug case

[Kuppuswamy, Sathyanarayanan]

On 3/28/20 3:21 PM, Bjorn Helgaas wrote:
> > > OK, thanks.  I'm still uncomfortable with this issue, so I think I'm
> > > going to apply this series but omit this patch.  Here's why:
> > >
> > > 1) The fact that resets may cause hotplug events isn't specific to
> > > DPC, so I don't think dpc_reset_link() is the right place.  For
> > > instance, aer_root_reset() ultimately does a secondary bus reset.
> > Agree. Reset is common for pci_channel_io_frozen errors. I did not
> > look into aer_root_reset() implementation. So if state
> > is pci_channel_io_frozen then we can assume the slot has been
> > reseted.
> >   The
> > > pci_slot_reset() -> pciehp_reset_slot() path goes to some trouble to
> > > ignore the resulting hotplug event, but the pci_bus_reset() path does
> > > not.
> > >
> > > 2) I'm not convinced that "hotplug_is_native()" is the correct test.
> > > Even if we're using ACPI hotplug (acpiphp), that will detach the
> > > drivers and remove the devices, won't it?
> > Yes, agreed. It does not handle ACPI hotplug case. In case of
> > ACPI hotplug, native_pcie_hotplug = 0. May be we need a new helper
> > function. hotplug_is_enabled() ?
> I'm not proposing the patch below to be applied.  I only included it
> as an idea of where the hotplug testing should be.
>
> I'm proposing to merge the pci/edr branch as-is, without these two
> patches:
>
>    PCI: move {pciehp,shpchp}_is_native() definitions to pci.c
>    PCI/DPC: Fix DPC recovery issue in non hotplug case
>
> accepting that we still have some issues in the non-hotplug case that
> we can fix later.
Ok. I am fine with it. Thanks for working on it.
>