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Commit e3d10505 authored by Dan Williams's avatar Dan Williams Committed by Greg Kroah-Hartman
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usb: fix hub-port pm_runtime_enable() vs runtime pm transitions 

Commit 9262c19d "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: 9262c19d ("usb: disable port power control if not supported in wHubCharacteristics")
Reported-by: default avatarBjørn Mork <bjorn@mork.no>
Reported-by: default avatarAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 6c79fe4a

drivers/usb/core/hub.c

+6 −0
Original line number Diff line number Diff line
@@ -1577,6 +1577,12 @@ static int hub_configure(struct usb_hub *hub, 
		}

	}

	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;

drivers/usb/core/hub.h

+2 −0
Original line number Diff line number Diff line
@@ -84,6 +84,7 @@ struct usb_hub { 
 * @dev: generic device interface

 * @port_owner: port's owner

 * @peer: related usb2 and usb3 ports (share the same connector)

 * @req: default pm qos request for hubs without port power control

 * @connect_type: port's connect type

 * @location: opaque representation of platform connector location

 * @status_lock: synchronize port_event() vs usb_port_{suspend|resume}
@@ -95,6 +96,7 @@ struct usb_port { 
	struct device dev;

	struct usb_dev_state *port_owner;

	struct usb_port *peer;

	struct dev_pm_qos_request *req;

	enum usb_port_connect_type connect_type;

	usb_port_location_t location;

	struct mutex status_lock;

drivers/usb/core/port.c

+46 −19
Original line number Diff line number Diff line
@@ -68,6 +68,7 @@ static void usb_port_device_release(struct device *dev) 
{

	struct usb_port *port_dev = to_usb_port(dev);



	kfree(port_dev->req);

	kfree(port_dev);

}
@@ -400,9 +401,13 @@ int usb_hub_create_port_device(struct usb_hub *hub, int port1) 
	int retval;



	port_dev = kzalloc(sizeof(*port_dev), GFP_KERNEL);

	if (!port_dev) {

		retval = -ENOMEM;

		goto exit;

	if (!port_dev)

		return -ENOMEM;



	port_dev->req = kzalloc(sizeof(*(port_dev->req)), GFP_KERNEL);

	if (!port_dev->req) {

		kfree(port_dev);

		return -ENOMEM;

	}



	hub->ports[port1 - 1] = port_dev;
@@ -418,31 +423,53 @@ int usb_hub_create_port_device(struct usb_hub *hub, int port1) 
			port1);

	mutex_init(&port_dev->status_lock);

	retval = device_register(&port_dev->dev);

	if (retval)

		goto error_register;

	if (retval) {

		put_device(&port_dev->dev);

		return retval;

	}



	/* Set default policy of port-poweroff disabled. */

	retval = dev_pm_qos_add_request(&port_dev->dev, port_dev->req,

			DEV_PM_QOS_FLAGS, PM_QOS_FLAG_NO_POWER_OFF);

	if (retval < 0) {

		device_unregister(&port_dev->dev);

		return retval;

	}



	find_and_link_peer(hub, port1);



	/*

	 * Enable runtime pm and hold a refernce that hub_configure()

	 * will drop once the PM_QOS_NO_POWER_OFF flag state has been set

	 * and the hub has been fully registered (hdev->maxchild set).

	 */

	pm_runtime_set_active(&port_dev->dev);

	pm_runtime_get_noresume(&port_dev->dev);

	pm_runtime_enable(&port_dev->dev);

	device_enable_async_suspend(&port_dev->dev);



	/*

	 * Do not enable port runtime pm if the hub does not support

	 * power switching.  Also, userspace must have final say of

	 * whether a port is permitted to power-off.  Do not enable

	 * runtime pm if we fail to expose pm_qos_no_power_off.

	 * Keep hidden the ability to enable port-poweroff if the hub

	 * does not support power switching.

	 */

	if (hub_is_port_power_switchable(hub)

			&& dev_pm_qos_expose_flags(&port_dev->dev,

			PM_QOS_FLAG_NO_POWER_OFF) == 0)

		pm_runtime_enable(&port_dev->dev);

	if (!hub_is_port_power_switchable(hub))

		return 0;



	device_enable_async_suspend(&port_dev->dev);

	/* Attempt to let userspace take over the policy. */

	retval = dev_pm_qos_expose_flags(&port_dev->dev,

			PM_QOS_FLAG_NO_POWER_OFF);

	if (retval < 0) {

		dev_warn(&port_dev->dev, "failed to expose pm_qos_no_poweroff\n");

		return 0;

	}



error_register:

	put_device(&port_dev->dev);

exit:

	return retval;

	/* Userspace owns the policy, drop the kernel 'no_poweroff' request. */

	retval = dev_pm_qos_remove_request(port_dev->req);

	if (retval >= 0) {

		kfree(port_dev->req);

		port_dev->req = NULL;

	}

	return 0;

}



void usb_hub_remove_port_device(struct usb_hub *hub, int port1)