Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 4.4 50/58] PCI: Check for PME in targeted sleep state | Date | Fri, 6 Jan 2017 22:44:35 +0100 |
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4.4-stable review patch. If anyone has any objections, please let me know.
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From: Alan Stern <stern@rowland.harvard.edu>
commit 6496ebd7edf446fccf8266a1a70ffcb64252593e upstream.
One some systems, the firmware does not allow certain PCI devices to be put in deep D-states. This can cause problems for wakeup signalling, if the device does not support PME# in the deepest allowed suspend state. For example, Pierre reports that on his system, ACPI does not permit his xHCI host controller to go into D3 during runtime suspend -- but D3 is the only state in which the controller can generate PME# signals. As a result, the controller goes into runtime suspend but never wakes up, so it doesn't work properly. USB devices plugged into the controller are never detected.
If the device relies on PME# for wakeup signals but is not capable of generating PME# in the target state, the PCI core should accurately report that it cannot do wakeup from runtime suspend. This patch modifies the pci_dev_run_wake() routine to add this check.
Reported-by: Pierre de Villemereuil <flyos@mailoo.org> Tested-by: Pierre de Villemereuil <flyos@mailoo.org> Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> CC: Lukas Wunner <lukas@wunner.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- drivers/pci/pci.c | 4 ++++ 1 file changed, 4 insertions(+)
--- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -2043,6 +2043,10 @@ bool pci_dev_run_wake(struct pci_dev *de if (!dev->pme_support) return false; + /* PME-capable in principle, but not from the intended sleep state */ + if (!pci_pme_capable(dev, pci_target_state(dev))) + return false; + while (bus->parent) { struct pci_dev *bridge = bus->self;
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