Re: [PATCH v15 0/4] Simplify PCIe native ownership

[Bjorn Helgaas <helgaas@kernel.org>]

On Fri, Oct 02, 2026 at 02:18:24PM -0700, Kuppuswamy Sathyanarayanan wrote:
> This revives Bjorn's v12 from November 2020, rebased onto v7.3-rc3.
> 
>   https://lore.kernel.org/all/20201126011816.711106-1-helgaas@kernel.org/
> 
> The goal is unchanged.  Decide who owns each PCIe port service in one
> place, when we interpret the _OSC results in acpi_pci_root_create(), so
> that everywhere else only has to look at host_bridge->native_X.  For AER
> specifically, host_bridge->native_aer becomes the single answer to the
> question "may Linux touch the AER Capability?".  Today callers each have
> to remember to also test pcie_ports_native and pci_aer_available().
> 
> I posted v11.  Bjorn took it over at v12, split the _OSC changes in two
> and deferred the "pcie_ports=dpc-native" work.  The v12 review comments
> were agreed but never respun, and the series stalled.  v13 was that
> respin.
> 
>   https://lore.kernel.org/r/cover.1603766889.git.sathyanarayanan.kuppuswamy@linux.intel.com [v11]
> 
> Bjorn suggested reviving it in response to Guixin Liu's report that
> "pcie_ports=native" no longer enables DPC.  The DPC service binds on
> host_bridge->native_aer, and that flag did not reflect the command line,
> so DPC stayed off when firmware retained AER control.  Patch 3 fixes it
> by making the flag reflect it.
> 
>   https://lore.kernel.org/linux-pci/20260901064554.2178688-1-kanie@linux.alibaba.com/
> 
> Patch 3 has a side effect worth calling out.  drivers/cxl/core/ras.c did
> not exist in 2020 and tests host_bridge->native_aer with no
> pcie_ports_native fallback, so it has been quietly ignoring
> "pcie_ports=native".  Centralizing the check fixes that.
> 
> Binding the DPC service on host_bridge->native_dpc, rather than on
> native_aer, is left for a separate patch on top of Lukas's series that
> removes the DPC/AER dependency, as agreed with Bjorn.  That change
> alters behavior, so it does not belong in this cleanup.
> 
>   https://lore.kernel.org/r/cover.1790531238.git.lukas@wunner.de
>   https://lore.kernel.org/r/20261001221408.GA2731929@bhelgaas
> 
> Changes since v14:
>   * Patch 3: fold "pcie_ports=dpc-native" into the _OSC control mask as
>     well, so host_bridge->native_dpc and the "OS native features" line
>     reflect it (Bjorn).
>   * Picked up Guixin's Reviewed-by on patch 3.
> 
> v14 posting
> https://lore.kernel.org/r/20260922204548.3884906-1-sathyanarayanan.kuppuswamy@linux.intel.com
> 
> Changes since v13:
>   * Lukas suggested dropping AER cap check fix (patch 1 of v13). He has
>     a series underway to fix it cleanly (removing DPC/AER dependency).
>     So dropped the patch as suggested.
>     https://lore.kernel.org/r/aq95LGUHL-pnmTlr@wunner.de
>   * Addressed use of IS_ENABLED(CONFIG_PCIEPORTBUS) instead of #ifdef
>     (Lukas).
>   * Added Fixes tag in patch 3 (Guixin Liu).
>   * Added Acks from Rafael.
> 
> v13 posting
> https://lore.kernel.org/r/20260919162655.3499010-1-sathyanarayanan.kuppuswamy@linux.intel.com
> 
> Bjorn Helgaas (1):
>   PCI: Centralize pci_aer_available() checking
> 
> Kuppuswamy Sathyanarayanan (3):
>   PCI: Assume control of portdrv-related features only when portdrv
>     enabled
>   PCI/ACPI: Tidy _OSC control bit checking
>   PCI/ACPI: Centralize pcie_ports_native checking
> 
>  drivers/acpi/pci_root.c           | 78 +++++++++++++++++++++++++------
>  drivers/pci/hotplug/pciehp_core.c |  2 +-
>  drivers/pci/pci-acpi.c            |  3 --
>  drivers/pci/pcie/aer.c            |  6 +--
>  drivers/pci/pcie/aer_cxl_rch.c    |  2 +-
>  drivers/pci/pcie/err.c            |  2 +-
>  drivers/pci/pcie/portdrv.c        |  7 ++-
>  drivers/pci/pcie/portdrv.h        |  2 -
>  drivers/pci/probe.c               | 10 ++--
>  include/linux/pci.h               |  2 +
>  10 files changed, 80 insertions(+), 34 deletions(-)

I put the first three patches on pci/portdrv for v7.4, thanks!

I deferred the last ("PCI: Centralize pci_aer_available() checking")
while we sort out the MSI/AER question, but I want to make sure we get
the rest in v7.4.