| From 6496ebd7edf446fccf8266a1a70ffcb64252593e Mon Sep 17 00:00:00 2001 |
| From: Alan Stern <stern@rowland.harvard.edu> |
| Date: Fri, 21 Oct 2016 16:45:38 -0400 |
| Subject: PCI: Check for PME in targeted sleep state |
| |
| 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; |
| |