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

[Bjorn Helgaas <helgaas@kernel.org>]

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/

>  		services |= PCIE_PORT_SERVICE_DPC;
>  
>  	/* Enable bandwidth control if more than one speed is supported. */
> -- 
> 2.43.7
>