usb: fix hub-port pm_runtime_enable() vs runtime pm transitions
Commit 9262c19d14c4 "usb: disable port power control if not supported in
wHubCharacteristics" gated enabling runtime pm for usb_port devices on
whether the parent hub supports power control, which causes a
regression. The port must still be allowed to carry out runtime pm
callbacks and receive a -EAGAIN or -EBUSY result. Otherwise the
usb_port device will transition to the pm error state and trigger the
same for the child usb_device.
Prior to the offending commit usb_hub_create_port_device() arranged for
runtime pm to be disabled is dev_pm_qos_expose_flags() failed. Instead,
force the default state of PM_QOS_FLAG_NO_POWER_OFF flag to be set prior
to enabling runtime pm. If that policy can not be set then fail
registration.
Report: http://marc.info/?l=linux-usb&m=140290586301336&w=2
Fixes: 9262c19d14c4 ("usb: disable port power control if not supported in wHubCharacteristics")
Reported-by: Bjørn Mork <bjorn@mork.no>
Reported-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 78c3cd2..21b99b4 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -1577,6 +1577,12 @@
}
}
hdev->maxchild = i;
+ for (i = 0; i < hdev->maxchild; i++) {
+ struct usb_port *port_dev = hub->ports[i];
+
+ pm_runtime_put(&port_dev->dev);
+ }
+
mutex_unlock(&usb_port_peer_mutex);
if (ret < 0)
goto fail;