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SubjectRe: [PATCH] PCI / PM: Disable wakeup during shutdown for devices not enabled to wake up
On Tue, 7 Feb 2012 00:50:35 +0100
"Rafael J. Wysocki" <rjw@sisk.pl> wrote:

> From: Rafael J. Wysocki <rjw@sisk.pl>
>
> If a PCI device is enabled to generate wakeup signals (PME) when put
> into a low-power state by runtime PM, it will be still enabled to
> generate those signals after the system shutdown, unless its driver's
> .shutdown() callback takes care of the wakeup signals generation
> setting. Moreover, there are devices that are not enabled to wake
> up the system and that are configured by runtime PM to generate
> wakeup signals so that (runtime) remote wakeup works with them.
> Those devices should be reconfigured during system shutdown so that
> they don't generate wakeup signals, but at least some drivers don't
> do that. However, that very well may be done by the PCI core so
> that drivers don't have to worry about it. For this reason, modify
> pci_device_shutdown() to disable the generation of wakeup events for
> devices not supposed to wake up the system.
>
> References: https://bugzilla.kernel.org/show_bug.cgi?id=37952
> Reported-and-tested-by: Kamil Iskra <kamil.54002@iskra.name>
> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
> ---
> drivers/pci/pci-driver.c | 10 ++++++++++
> 1 file changed, 10 insertions(+)
>
> Index: linux/drivers/pci/pci-driver.c
> ===================================================================
> --- linux.orig/drivers/pci/pci-driver.c
> +++ linux/drivers/pci/pci-driver.c
> @@ -430,6 +430,16 @@ static void pci_device_shutdown(struct d
> drv->shutdown(pci_dev);
> pci_msi_shutdown(pci_dev);
> pci_msix_shutdown(pci_dev);
> +
> + /*
> + * Devices may be enabled to wake up by runtime PM, but they need not
> + * be supposed to wake up the system from its "power off" state (e.g.
> + * ACPI S5). Therefore disable wakeup for all devices that aren't
> + * supposed to wake up the system at this point. The state argument
> + * will be ignored by pci_enable_wake().
> + */
> + if (!device_may_wakeup(dev))
> + pci_enable_wake(pci_dev, PCI_UNKNOWN, false);
> }
>
> #ifdef CONFIG_PM
>

So where do we end up setting the right wakeup state for devices we
actually *do* want to wake the system from S5? Presumably later in the
shutdown sequence?

--
Jesse Barnes, Intel Open Source Technology Center
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