[ Upstream commit 6496ebd7ed ]
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: stable@vger.kernel.org
CC: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
8537ab5ad7