Patch "PCI: Check for PME in targeted sleep state" has been added to the 4.9-stable tree

This is a note to let you know that I've just added the patch titled

PCI: Check for PME in targeted sleep state

to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
pci-check-for-pme-in-targeted-sleep-state.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Alan Stern <[email protected]>
Date: Fri, 21 Oct 2016 16:45:38 -0400
Subject: PCI: Check for PME in targeted sleep state

From: Alan Stern <[email protected]>

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.

---
 drivers/pci/pci.c |    4 ++++
 1 file changed, 4 insertions(+)

@@ -2106,6 +2106,10 @@ 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;
 

Patches currently in stable-queue which might be from [email protected] are

queue-4.9/pci-check-for-pme-in-targeted-sleep-state.patch