On Mon, May 07, 2018 at 02:11:20PM +0800, Kai-Heng Feng wrote:

USB controller ASM1042 stops working after commit de3ef1eb1cd0 ("PM / core: Drop run_wake flag from struct dev_pm_info").

The device in question is not power managed by platform firmware, furthermore, it only supports PME# from D3cold: Capabilities: [78] Power Management version 3 Flags: PMEClk- DSI- D1- D2- AuxCurrent=55mA PME(D0-,D1-,D2-,D3hot-,D3cold+) Status: D0 NoSoftRst+ PME-Enable- DSel=0 DScale=0 PME-

Before commit de3ef1eb1cd0, the device never gets runtime suspended. After that commit, the device gets runtime suspended to D3hot, which can not generate any PME#.

usb_hcd_pci_probe() unconditionally calls device_wakeup_enable(), hence device_can_wakeup() in pci_dev_run_wake() always returns true.

So pci_dev_run_wake() needs to check PME wakeup capability as its first condition.

In addition, change wakeup flag passed to pci_target_state() from false to true, because we want to find the deepest state that the device can still generate PME#. In this case, it's D0 for the device in question.

Fixes: de3ef1eb1cd0 ("PM / core: Drop run_wake flag from struct dev_pm_info") Cc: stable@vger.kernel.org # 4.13+ Signed-off-by: Kai-Heng Feng kai.heng.feng@canonical.com

Acked-by: Bjorn Helgaas bhelgaas@google.com

Rafael, can you queue this up? de3ef1eb1cd0 went through your tree, and I don't really understand the patch, so I'll rely on your review.

---

v4: Correct some errors in commit log.

v3: State the reason why the wakeup flag gets changed.

v2: Explicitly check dev->pme_support.

drivers/pci/pci.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index a04197ce767d..c2616cad3a1d 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -2138,16 +2138,16 @@ bool pci_dev_run_wake(struct pci_dev *dev) { struct pci_bus *bus = dev->bus;

• if (device_can_wakeup(&dev->dev))

• return true;
  

• if (!dev->pme_support) return false;

/* PME-capable in principle, but not from the target power state */

• if (!pci_pme_capable(dev, pci_target_state(dev, false)))

• if (!pci_pme_capable(dev, pci_target_state(dev, true))) return false;

• if (device_can_wakeup(&dev->dev))

• return true;
  

• while (bus->parent) { struct pci_dev *bridge = bus->self;

2.17.0