From: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
This patch has been added to the 3.12 stable tree. If you have any
objections, please let us know.
===============
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@xxxxxxxxxx>
Tested-by: Pierre de Villemereuil <flyos@xxxxxxxxxx>
Signed-off-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
CC: Lukas Wunner <lukas@xxxxxxxxx>
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
---
drivers/pci/pci.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 36c3e71d54b5..1b9548fb9102 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -1906,6 +1906,10 @@ bool pci_dev_run_wake(struct pci_dev *dev)
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;
--
2.11.0
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