PCI: Check for PME in targeted sleep state

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: Ben Hutchings <ben@decadent.org.uk>

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 4c3a9e9..6b72e4a 100644 (file)
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -1763,6 +1763,10 @@ bool pci_dev_run_wake(struct pci_dev *dev)
        if (!dev->pme_support)
                return false;
 
        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;
 
        while (bus->parent) {
                struct pci_dev *bridge = bus->self;