Re: [PATCH v2 6/6] PCI/portdrv: Bind DPC service based on host_bridge->native_dpc

[sashiko-bot@kernel.org]

> get_port_device_capability() binds the DPC service if the port has a DPC
> capability and either "pcie_ports=dpc-native" was given or the OS
> controls AER.  This repeats decisions that are already made elsewhere.
> It also ignores host_bridge->native_dpc, which is meant to say whether
> the OS owns DPC.
> 
> Make host_bridge->native_dpc the single decider:
> 
>   - In acpi_pci_root_create(), assume DPC control whenever _OSC grants
>     AER control.  PCI Firmware r3.3, sec 4.5.2.4, requires platforms to
>     retain AER if they retain DPC.  Put the other way, firmware that
>     grants AER does not keep DPC.  PCIe r7.0 sec 6.2.11 recommends that
>     the OS link control of DPC to control of AER.  Commit 97ca178c899d
>     ("PCI/DPC: Allow DPC on all Downstream Ports when OS controls AER")
>     relied on this link.  Keeping it means DPC still works with firmware
> [ ... ]
> this.  The OS now uses DPC there because firmware granted it.  Since
> "PCI/DPC: Reinstate support for AER-incapable ports", dpc_probe() no
> longer requires AER control.
> 
> Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>

Sashiko has reviewed this patch and found no issues.

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