From: Mika Westerberg mika.westerberg@linux.intel.com
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
--- drivers/pci/pci.c | 7 +++++++ 1 file changed, 7 insertions(+)
--- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -1736,6 +1736,13 @@ static void pci_pme_list_scan(struct wor */ 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);