lkml.org 
[lkml]   [2018]   [Mar]   [8]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH v1 2/9] PCI/PM: Clear PCIe PME Status bit in core, not PCIe port driver
On Wed, Mar 07, 2018 at 12:13:34AM -0600, Bjorn Helgaas wrote:
> From: Bjorn Helgaas <bhelgaas@google.com>
>
> fe31e69740ed ("PCI/PCIe: Clear Root PME Status bits early during system
> resume") added a .resume_noirq() callback to the PCIe port driver to clear
> the PME Status bit during resume to work around a BIOS issue.
>
> The BIOS evidently enabled PME interrupts for ACPI-based runtime wakeups
> but did not clear the PME Status bit during resume, which meant PMEs after
> resume did not trigger interrupts because PME Status did not transition
> from cleared to set.
>
> The fix was in the PCIe port driver, so it worked when CONFIG_PCIEPORTBUS
> was set. But I think we *always* want the fix because the platform may use
> PME interrupts even if Linux is built without the PCIe port driver.
>
> Move the fix from the port driver to the PCI core so we can work around
> this "PME doesn't work after waking from a sleep state" issue regardless of
> CONFIG_PCIEPORTBUS.
>
> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
> ---
> drivers/pci/pci-driver.c | 14 ++++++++++++++
> drivers/pci/pcie/portdrv_pci.c | 15 ---------------
> 2 files changed, 14 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
> index 3bed6beda051..bf0704b75f79 100644
> --- a/drivers/pci/pci-driver.c
> +++ b/drivers/pci/pci-driver.c
> @@ -525,6 +525,18 @@ static void pci_pm_default_resume_early(struct pci_dev *pci_dev)
> pci_fixup_device(pci_fixup_resume_early, pci_dev);
> }
>
> +static void pcie_resume_early(struct pci_dev *pci_dev)
> +{
> + /*
> + * Some BIOSes forget to clear Root PME Status bits after system wakeup
> + * which breaks ACPI-based runtime wakeup on PCI Express, so clear those
> + * bits now just in case (shouldn't hurt).
> + */
> + if (pci_is_pcie(pci_dev) &&
> + pci_pcie_type(pci_dev) == PCI_EXP_TYPE_ROOT_PORT)
> + pcie_clear_root_pme_status(pci_dev);
> +}
> +
> /*
> * Default "suspend" method for devices that have no driver provided suspend,
> * or not even a driver at all (second part).
> @@ -873,6 +885,8 @@ static int pci_pm_resume_noirq(struct device *dev)
> if (pci_has_legacy_pm_support(pci_dev))
> return pci_legacy_resume_early(dev);
>
> + pcie_resume_early(pci_dev);

I'm wondering if it would be better to implement this as a PCI quirk:

DECLARE_PCI_FIXUP_CLASS_RESUME_EARLY(PCI_ANY_ID, PCI_ANY_ID,
PCI_CLASS_BRIDGE_PCI, 8, ...)

Then it would also be executed for the ->restore_noirq phase, not only
->resume_noirq. And it could be constrained to only the affected PCI
or DMI IDs.

However it would then also be executed on ->runtime_resume, I'm not
sure if that's a problem or not.

Thanks,

Lukas

> +
> if (drv && drv->pm && drv->pm->resume_noirq)
> error = drv->pm->resume_noirq(dev);
>
> diff --git a/drivers/pci/pcie/portdrv_pci.c b/drivers/pci/pcie/portdrv_pci.c
> index 4413dd85e923..f91afd09e356 100644
> --- a/drivers/pci/pcie/portdrv_pci.c
> +++ b/drivers/pci/pcie/portdrv_pci.c
> @@ -62,20 +62,6 @@ static int pcie_portdrv_restore_config(struct pci_dev *dev)
> }
>
> #ifdef CONFIG_PM
> -static int pcie_port_resume_noirq(struct device *dev)
> -{
> - struct pci_dev *pdev = to_pci_dev(dev);
> -
> - /*
> - * Some BIOSes forget to clear Root PME Status bits after system wakeup
> - * which breaks ACPI-based runtime wakeup on PCI Express, so clear those
> - * bits now just in case (shouldn't hurt).
> - */
> - if (pci_pcie_type(pdev) == PCI_EXP_TYPE_ROOT_PORT)
> - pcie_clear_root_pme_status(pdev);
> - return 0;
> -}
> -
> static int pcie_port_runtime_suspend(struct device *dev)
> {
> return to_pci_dev(dev)->bridge_d3 ? 0 : -EBUSY;
> @@ -103,7 +89,6 @@ static const struct dev_pm_ops pcie_portdrv_pm_ops = {
> .thaw = pcie_port_device_resume,
> .poweroff = pcie_port_device_suspend,
> .restore = pcie_port_device_resume,
> - .resume_noirq = pcie_port_resume_noirq,
> .runtime_suspend = pcie_port_runtime_suspend,
> .runtime_resume = pcie_port_runtime_resume,
> .runtime_idle = pcie_port_runtime_idle,
>

\
 
 \ /
  Last update: 2018-03-08 09:04    [W:0.071 / U:2.436 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site