PCI/PM: Do not suspend port if any subordinate device needs PME polling
authorHuang Ying <ying.huang@intel.com>
Wed, 26 Dec 2012 17:39:23 +0000 (10:39 -0700)
committerBjorn Helgaas <bhelgaas@google.com>
Wed, 26 Dec 2012 17:39:23 +0000 (10:39 -0700)
commitc733b77475707cc3980542c86ee0ad5c841d544c
tree5a2fed17d994e0e88737283b3af5f0fa20375cb1
parent130f1b8f35f14d27c43da755f3c9226318c17f57
PCI/PM: Do not suspend port if any subordinate device needs PME polling

Ulrich reported that his USB3 cardreader does not work reliably when
connected to the USB3 port.  It turns out that USB3 controller failed to
awaken when plugging in the USB3 cardreader.  Further experiments found
that the USB3 host controller can only be awakened via polling, not via PME
interrupt.  But if the PCIe port to which the USB3 host controller is
connected is suspended, we cannot poll the controller because its config
space is not accessible when the PCIe port is in a low power state.

To solve the issue, the PCIe port will not be suspended if any subordinate
device needs PME polling.

[bhelgaas: use bool consistently rather than mixing int/bool]
Reference: http://lkml.kernel.org/r/50841CCC.9030809@uli-eckhardt.de
Reported-by: Ulrich Eckhardt <usb@uli-eckhardt.de>
Tested-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: Huang Ying <ying.huang@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
CC: stable@vger.kernel.org # v3.6+
drivers/pci/pcie/portdrv_pci.c