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

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