On Thursday, September 6, 2018 5:50:11 PM CEST Mika Westerberg wrote:
> Commit baecc470d5fd ("PCI / PM: Skip bridges in pci_enable_wake()")
> changed pci_enable_wake() so that all bridges are skipped when wakeup is
> enabled (or disabled) with the reasoning that bridges can only signal
> wakeup on behalf of their subordinate devices.
>
> However, there are bridges that can signal wakeup itself. For example
> PCIe downstream and root ports supporting hotplug may signal wakeup upon
> hotplug event.
>
> For this reason change pci_enable_wake() so that it skips all bridges
> except those that we power manage (->bridge_d3 is set). Those are the
> ones that can go into low power states and may need to signal wakeup.
>
> Signed-off-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
> ---
> drivers/pci/pci.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index 29ff9619b5fa..074f3f0253f9 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -2134,9 +2134,11 @@ static int __pci_enable_wake(struct pci_dev *dev, pci_power_t state, bool enable
>
> /*
> * Bridges can only signal wakeup on behalf of subordinate devices,
> - * but that is set up elsewhere, so skip them.
> + * but that is set up elsewhere, so skip them. With the exception
> + * of bridges that we power manage. These can signal wake for
> + * example on a hotplug event.
> */
I would change the comment even more, to something like:
"Bridges that are not power-manageable directly only signal wakeup on behalf
of subordinate devices which is set up elsewhere, so skip them. However,
bridges that are power-manageable may signal wakeup for themselves (for example,
on a hotplug event) and they need to be covered here."
> - if (pci_has_subordinate(dev))
> + if (!pci_power_manageable(dev))
> return 0;
>
> /* Don't do the same thing twice in a row for one device. */
>
