PCI: Do not poll for PME if the device is in D3cold

commit 000dd5316e1c756a1c028f22e01d06a38249dd4d upstream.

PME polling does not take into account that a device that is directly
connected to the host bridge may go into D3cold as well. This leads to a
situation where the PME poll thread reads from a config space of a
device that is in D3cold and gets incorrect information because the
config space is not accessible.

Here is an example from Intel Ice Lake system where two PCIe root ports
are in D3cold (I've instrumented the kernel to log the PMCSR register
contents):

  [   62.971442] pcieport 0000:00:07.1: Check PME status, PMCSR=0xffff
  [   62.971504] pcieport 0000:00:07.0: Check PME status, PMCSR=0xffff

Since 0xffff is interpreted so that PME is pending, the root ports will
be runtime resumed. This repeats over and over again essentially
blocking all runtime power management.

Prevent this from happening by checking whether the device is in D3cold
before its PME status is read.

Fixes: 71a83bd727cc ("PCI/PM: add runtime PM support to PCIe port")
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Lukas Wunner <lukas@wunner.de>
Cc: 3.6+ <stable@vger.kernel.org> # v3.6+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 1af30c8815665eea6e7deab98cdf2d29c81e253d..044b208f7f6a21ced2f85c76be27694801fc071d 100644 (file)
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -1786,6 +1786,13 @@ static void pci_pme_list_scan(struct work_struct *work)
                         */
                        if (bridge && bridge->current_state != PCI_D0)
                                continue;
+                       /*
+                        * If the device is in D3cold it should not be
+                        * polled either.
+                        */
+                       if (pme_dev->dev->current_state == PCI_D3cold)
+                               continue;
+
                        pci_pme_wakeup(pme_dev->dev, NULL);
                } else {
                        list_del(&pme_dev->list);