PCI / PM: Always check PME wakeup capability for runtime wakeup support
authorKai Heng Feng <kai.heng.feng@canonical.com>
Mon, 7 May 2018 06:11:20 +0000 (14:11 +0800)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Wed, 16 May 2018 08:10:29 +0000 (10:10 +0200)
commit89d5c4eb810589fd43e91e14feb7cd1923dc3587
treea965f675aa95f428feef271d40ce9d23ae71abc3
parente2023117b877dde94050b96e15948c0a44961a6d
PCI / PM: Always check PME wakeup capability for runtime wakeup support

commit 8feaec33b9868582654cd3d5355225dcb79aeca6 upstream.

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 different from D3cold
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)
Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Cc: 4.13+ <stable@vger.kernel.org> # 4.13+
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/pci/pci.c