Re: [PATCH] PCI/DPC: Honor "pcie_ports=native" when enabling DPC

[Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>]

Hi Liu,

On 9/14/2026 4:01 AM, Guixin Liu wrote:
> 
> 
> 在 2026/9/4 10:34, Guixin Liu 写道:
>>
>>
>> 在 2026/9/4 07:05, Bjorn Helgaas 写道:
>>> On Tue, Sep 01, 2026 at 02:45:54PM +0800, Guixin Liu wrote:
>>>> Commit 97ca178c899d ("PCI/DPC: Allow DPC on all Downstream Ports when
>>>> OS controls AER") replaced the AER service bit with host->native_aer
>>>> when deciding whether to create a DPC service device. Unlike the AER
>>>> service bit, host->native_aer does not reflect the "pcie_ports=native"
>>>> command-line override.
>>>>
>>>> Consequently, if firmware retains AER control, "pcie_ports=native" no
>>>> longer enables DPC on Root Ports that advertise both AER and DPC, even
>>>> though the option is documented to force native DPC handling.
>>>>
>>>> Check pcie_ports_native explicitly so both command-line overrides
>>>> continue to work.
>>>>
>>>> Fixes: 97ca178c899d ("PCI/DPC: Allow DPC on all Downstream Ports when OS controls AER")
>>>> Cc: stable@vger.kernel.org
>>>> Signed-off-by: Guixin Liu <kanie@linux.alibaba.com>
>>>> ---
>>>>   drivers/pci/pcie/portdrv.c | 2 +-
>>>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>>>
>>>> diff --git a/drivers/pci/pcie/portdrv.c b/drivers/pci/pcie/portdrv.c
>>>> index a9cbfc1d2bc7..a05ee7980fb2 100644
>>>> --- a/drivers/pci/pcie/portdrv.c
>>>> +++ b/drivers/pci/pcie/portdrv.c
>>>> @@ -264,7 +264,7 @@ static int get_port_device_capability(struct pci_dev *dev)
>>>>        */
>>>>       if (pci_find_ext_capability(dev, PCI_EXT_CAP_ID_DPC) &&
>>>>           pci_aer_available() &&
>>>> -        (pcie_ports_dpc_native || host->native_aer))
>>>> +        (pcie_ports_native || pcie_ports_dpc_native || host->native_aer))
>>> Oh my goodness.  I think I completely dropped ball on this YEARS ago.
>>>
>>> It's crazy that we have "pcie_ports_native" checking littered all
>>> over.  I think we should instead treat host->native_* as the single
>>> source of truth, and pay attention to pcie_ports_native when setting
>>> host->native_*.
>>>
>>> Sathy did some great work to do exactly that in 2020, and I never got
>>> it merged.  I wish I had some great excuse, but I looked at my 2020
>>> calendar and couldn't find one.  I think I just blew it.
>>>
>>> So I think we should resurrect that series and update it as needed and
>>> solve the problem that way.  I dug out the links just for
>>> completeness, but we should probably just start with the most recent
>>> ones (v11 or v12):
>>>
>>>    # v2 https://lore.kernel.org/r/cover.1590355211.git.sathyanarayanan.kuppuswamy@linux.intel.com/
>>>    # v3 https://lore.kernel.org/r/cover.1590355824.git.sathyanarayanan.kuppuswamy@linux.intel.com/
>>>    # v4 https://lore.kernel.org/r/cover.1590534843.git.sathyanarayanan.kuppuswamy@linux.intel.com/
>>>    # v5 https://lore.kernel.org/r/cover.1591545462.git.sathyanarayanan.kuppuswamy@linux.intel.com/
>>>    # v6 https://lore.kernel.org/r/cover.1593195899.git.sathyanarayanan.kuppuswamy@linux.intel.com/
>>>    # v7 https://lore.kernel.org/r/cover.1595006564.git.sathyanarayanan.kuppuswamy@linux.intel.com/
>>>    # v8 https://lore.kernel.org/r/cover.1595649348.git.sathyanarayanan.kuppuswamy@linux.intel.com/
>>>    # v9 https://lore.kernel.org/r/cover.1600457297.git.sathyanarayanan.kuppuswamy@linux.intel.com/
>>>    # v9 https://lore.kernel.org/r/20200928011131.MI-pJpJNRQw6c35j_O6019flLWHe08C4WvKPmKEbnik@z/
>>>    # v10 https://lore.kernel.org/r/cover.1603738449.git.sathyanarayanan.kuppuswamy@linux.intel.com/
>>>    # v11 https://lore.kernel.org/r/cover.1603766889.git.sathyanarayanan.kuppuswamy@linux.intel.com/
>>>    # v12 https://lore.kernel.org/r/20201126011816.711106-1-helgaas@kernel.org/
> Hi Bjorn, still not see you resurrect this series.

I am working on this. I will post the rebased version soon.

> 
> Best Regards,
> Guixin Liu
>> Yeah, this series is better than mine, wait for your to recover them.
>>
>> In addition, we should add "Fixes: 97ca178c899d ("PCI/DPC: Allow DPC on all Downstream Ports when OS controls AER")" also.
>>
>> Best Regards,
>> Guixin Liu
>>>> services |= PCIE_PORT_SERVICE_DPC;
>>>>         /* Enable bandwidth control if more than one speed is supported. */
>>>> -- 
>>>> 2.43.7
>>>>
> 

-- 
Sathyanarayanan Kuppuswamy
Linux Kernel Developer