linux-kernel - Re: [PATCH v1 3/9] PCI/PM: Clear PCIe PME Status bit for Root Complex Event Collectors

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Date:   Wed, 07 Mar 2018 11:27:51 +0100
From:   "Rafael J. Wysocki" <rjw@...ysocki.net>
To:     Bjorn Helgaas <helgaas@...nel.org>
Cc:     linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-pm@...r.kernel.org, Keith Busch <keith.busch@...el.com>,
        Sinan Kaya <okaya@...eaurora.org>,
        Lukas Wunner <lukas@...ner.de>
Subject: Re: [PATCH v1 3/9] PCI/PM: Clear PCIe PME Status bit for Root Complex Event Collectors

On Wednesday, March 7, 2018 7:13:40 AM CET Bjorn Helgaas wrote:
> From: Bjorn Helgaas <bhelgaas@...gle.com>
> 
> Per PCIe r4.0, sec 6.1.6, Root Complex Event Collectors can generate PME
> interrupts on behalf of Root Complex Integrated Endpoints.
> 
> Linux does not currently enable PME interrupts from RC Event Collectors,
> but fe31e69740ed ("PCI/PCIe: Clear Root PME Status bits early during system
> resume") suggests PME interrupts may be enabled by the platform for ACPI-
> based runtime wakeup.
> 
> Clear the PCIe PME Status bit for Root Complex Event Collectors during
> resume, just like we already do for Root Ports.
> 
> If the BIOS enables PME interrupts for an event collector and neglects to
> clear the status bit on resume, this change should fix the same bug as
> fe31e69740ed (PMEs not working after waking from a sleep state), but for
> Root Complex Integrated Endpoints.
> 
> Signed-off-by: Bjorn Helgaas <bhelgaas@...gle.com>
> ---
>  drivers/pci/pci-driver.c |    3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
> index bf0704b75f79..38ee7c8b4d1a 100644
> --- a/drivers/pci/pci-driver.c
> +++ b/drivers/pci/pci-driver.c
> @@ -533,7 +533,8 @@ static void pcie_resume_early(struct pci_dev *pci_dev)
>  	 * bits now just in case (shouldn't hurt).
>  	 */
>  	if (pci_is_pcie(pci_dev) &&
> -	    pci_pcie_type(pci_dev) == PCI_EXP_TYPE_ROOT_PORT)
> +	    (pci_pcie_type(pci_dev) == PCI_EXP_TYPE_ROOT_PORT ||
> +	     pci_pcie_type(pci_dev) == PCI_EXP_TYPE_RC_EC))
>  		pcie_clear_root_pme_status(pci_dev);
>  }
>  
> 
> 

Reveiwed-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>