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Message-ID: <CAAd53p7sPoH-MD9VMh1u+mf_E7Mc2xVfkHbhN4PCdxQM+v274g@mail.gmail.com>
Date: Thu, 21 Oct 2021 14:56:47 +0800
From: Kai-Heng Feng <kai.heng.feng@...onical.com>
To: Bjorn Helgaas <bhelgaas@...gle.com>
Cc: Lukas Wunner <lukas@...ner.de>,
Mika Westerberg <mika.westerberg@...ux.intel.com>,
"Rafael J . Wysocki" <rafael.j.wysocki@...el.com>,
"open list:PCI SUBSYSTEM" <linux-pci@...r.kernel.org>,
open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2] PCI: Check PCIe upstream port for PME support
On Thu, Aug 12, 2021 at 11:39 PM Kai-Heng Feng
<kai.heng.feng@...onical.com> wrote:
>
> Some platforms cannot detect ethernet hotplug once its upstream port is
> runtime suspended because PME isn't granted by BIOS _OSC. The issue can
> be workarounded by "pcie_ports=native".
>
> The vendor confirmed that the PME in _OSC is disabled intentionally for
> system stability issues on the other OS, so we should also honor the PME
> setting here.
>
> So before marking PME support status for the device, check
> PCI_EXP_RTCTL_PMEIE bit to ensure PME interrupt is either enabled by
> firmware or OS.
>
> Cc: Lukas Wunner <lukas@...ner.de>
> Cc: Mika Westerberg <mika.westerberg@...ux.intel.com>
> Cc: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=213873
> Signed-off-by: Kai-Heng Feng <kai.heng.feng@...onical.com>
A gentle ping...
> ---
> v2:
> - Instead of prevent root port from runtime suspending, skip
> initializing PME status for the downstream device.
>
> drivers/pci/pci.c | 28 +++++++++++++++++++++++++++-
> 1 file changed, 27 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index aacf575c15cf..4344dc302edd 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -2294,6 +2294,32 @@ void pci_pme_wakeup_bus(struct pci_bus *bus)
> pci_walk_bus(bus, pci_pme_wakeup, (void *)true);
> }
>
> +#ifdef CONFIG_PCIE_PME
> +static bool pci_pcie_port_pme_enabled(struct pci_dev *dev)
> +{
> + struct pci_dev *bridge = pci_upstream_bridge(dev);
> + u16 val;
> + int ret;
> +
> + if (!bridge)
> + return true;
> +
> + if (pci_pcie_type(bridge) != PCI_EXP_TYPE_ROOT_PORT &&
> + pci_pcie_type(bridge) != PCI_EXP_TYPE_RC_EC)
> + return true;
> +
> + ret = pcie_capability_read_word(bridge, PCI_EXP_RTCTL, &val);
> + if (ret)
> + return false;
> +
> + return val & PCI_EXP_RTCTL_PMEIE;
> +}
> +#else
> +static bool pci_pcie_port_pme_enabled(struct pci_dev *dev)
> +{
> + return true;
> +}
> +#endif
>
> /**
> * pci_pme_capable - check the capability of PCI device to generate PME#
> @@ -3095,7 +3121,7 @@ void pci_pm_init(struct pci_dev *dev)
> }
>
> pmc &= PCI_PM_CAP_PME_MASK;
> - if (pmc) {
> + if (pmc && pci_pcie_port_pme_enabled(dev)) {
> pci_info(dev, "PME# supported from%s%s%s%s%s\n",
> (pmc & PCI_PM_CAP_PME_D0) ? " D0" : "",
> (pmc & PCI_PM_CAP_PME_D1) ? " D1" : "",
> --
> 2.32.0
>
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