Re: [PATCH v15 1/4] PCI: Assume control of portdrv-related features only when portdrv enabled

[Lukas Wunner <lukas@wunner.de>]

On Fri, Oct 02, 2026 at 02:18:25PM -0700, Kuppuswamy Sathyanarayanan wrote:
> Native control of PME, AER, DPC, and PCIe hotplug depends on the portdrv,
> so default to native handling of them only when CONFIG_PCIEPORTBUS is
> enabled.
> 
> Native control of LTR and SHPC hotplug does not depend on portdrv, so keep
> defaulting those to native regardless.
> 
> [bhelgaas: commit log]
> Link: https://lore.kernel.org/r/fcbe8a624166a1101a755edfef44a185d32ff493.1603766889.git.sathyanarayanan.kuppuswamy@linux.intel.com
> Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

This is now commit 6347fd9aee19 in Linus' tree and I think there's a problem:

> +++ b/drivers/pci/probe.c
> @@ -658,6 +658,8 @@ static const struct device_type pci_host_bridge_type = {
>  
>  static void pci_init_host_bridge(struct pci_host_bridge *bridge)
>  {
> +	bool port_services = IS_ENABLED(CONFIG_PCIEPORTBUS);
> +
>  	INIT_LIST_HEAD(&bridge->windows);
>  	INIT_LIST_HEAD(&bridge->dma_ranges);
>  	INIT_LIST_HEAD(&bridge->ports);
> @@ -668,12 +670,12 @@ static void pci_init_host_bridge(struct pci_host_bridge *bridge)
>  	 * may implement its own AER handling and use _OSC to prevent the
>  	 * OS from interfering.
>  	 */
> -	bridge->native_aer = 1;
> -	bridge->native_pcie_hotplug = 1;
> +	bridge->native_aer = port_services;
> +	bridge->native_pcie_hotplug = port_services;

The commit is setting the native_pcie_hotplug bit up front based on
CONFIG_PCIEPORTBUS.

But there's an if-clause at the top of get_port_device_capability() which
adds PCIE_PORT_SERVICE_HP to the port services used by a given PCIe port.

Inside the if-clause is code to disable hotplug interrupts if the BIOS
left them enable.

Since the commit, if CONFIG_PCIEPORTBUS=n, the if-clause is no longer
entered and so the interrupts are no longer disabled.

I'm amazed sashiko didn't flag this.  I didn't spot it during review
either, but noticed it when rebasing my development branch.  I still
have a patch on that branch which I developed last year but which
was ultimately not accepted (for good reasons).  Back then I already
noticed that the interrupt disablement issue prevented simplification
of native_pcie_hotplug initialization.  I forgot about it but had to
revisit the patch when rebasing the development branch on top of your
patches:

https://lore.kernel.org/r/5eae82776d695e589b89aad500d8208b980347e5.1752390102.git.lukas@wunner.de

Now what?  The offending patch is the first one in a series of three.
Revert all three or can we somehow salvage this?

Thanks,

Lukas