Commit 7ad3c470 authored by Dan Williams's avatar Dan Williams Committed by Greg Kroah-Hartman
Browse files

usb: block suspension of superspeed port while hispeed peer is active 



ClearPortFeature(PORT_POWER) on a usb3 port places the port in either a
DSPORT.Powered-off-detect / DSPORT.Powered-off-reset loop, or the
DSPORT.Powered-off state.  There is no way to ensure that RX
terminations will persist in this state, so it is possible a device will
degrade to its usb2 connection.  Prevent this by blocking power-off of a
usb3 port while its usb2 peer is active, and powering on a usb3 port
before its usb2 peer.

By default the latency between peer power-on events is 0.  In order for
the device to not see usb2 active while usb3 is still powering up inject
the hub recommended power_on_good delay.  In support of satisfying the
power_on_good delay outside of hub_power_on() refactor the places where
the delay is consumed to call a new hub_power_on_good_delay() helper.

Finally, because this introduces several new checks for whether a port
is_superspeed, cache that disctinction at port creation so that we don't
need to keep looking up the parent hub device.

Acked-by: default avatarAlan Stern <stern@rowland.harvard.edu>
[alan]: add a 'superspeed' flag to the port
Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent d5c3834e

drivers/usb/core/hub.c

+5 −17
Original line number Diff line number Diff line
@@ -36,11 +36,6 @@ 
#define USB_VENDOR_GENESYS_LOGIC		0x05e3

#define HUB_QUIRK_CHECK_PORT_AUTOSUSPEND	0x01



static inline int hub_is_superspeed(struct usb_device *hdev)

{

	return (hdev->descriptor.bDeviceProtocol == USB_HUB_PR_SS);

}



/* Protect struct usb_device->state and ->children members

 * Note: Both are also protected by ->dev.sem, except that ->state can

 * change to USB_STATE_NOTATTACHED even when the semaphore isn't held. */
@@ -822,14 +817,9 @@ int usb_hub_clear_tt_buffer(struct urb *urb) 
}

EXPORT_SYMBOL_GPL(usb_hub_clear_tt_buffer);



/* If do_delay is false, return the number of milliseconds the caller

 * needs to delay.

 */

static unsigned hub_power_on(struct usb_hub *hub, bool do_delay)

static void hub_power_on(struct usb_hub *hub, bool do_delay)

{

	int port1;

	unsigned pgood_delay = hub->descriptor->bPwrOn2PwrGood * 2;

	unsigned delay;



	/* Enable power on each port.  Some hubs have reserved values

	 * of LPSM (> 2) in their descriptors, even though they are
@@ -848,12 +838,8 @@ static unsigned hub_power_on(struct usb_hub *hub, bool do_delay) 
		else

			usb_clear_port_feature(hub->hdev, port1,

						USB_PORT_FEAT_POWER);



	/* Wait at least 100 msec for power to become stable */

	delay = max(pgood_delay, (unsigned) 100);

	if (do_delay)

		msleep(delay);

	return delay;

		msleep(hub_power_on_good_delay(hub));

}



static int hub_hub_status(struct usb_hub *hub,
@@ -1057,7 +1043,9 @@ static void hub_activate(struct usb_hub *hub, enum hub_activation_type type) 
		 * for HUB_POST_RESET, but it's easier not to.

		 */

		if (type == HUB_INIT) {

			delay = hub_power_on(hub, false);

			unsigned delay = hub_power_on_good_delay(hub);



			hub_power_on(hub, false);

			INIT_DELAYED_WORK(&hub->init_work, hub_init_func2);

			queue_delayed_work(system_power_efficient_wq,

					&hub->init_work,

drivers/usb/core/hub.h

+15 −0
Original line number Diff line number Diff line
@@ -89,6 +89,7 @@ struct usb_hub { 
 * @connect_type: port's connect type

 * @location: opaque representation of platform connector location

 * @portnum: port index num based one

 * @is_superspeed cache super-speed status

 */

struct usb_port {

	struct usb_device *child;
@@ -98,6 +99,7 @@ struct usb_port { 
	enum usb_port_connect_type connect_type;

	usb_port_location_t location;

	u8 portnum;

	unsigned int is_superspeed:1;

};



#define to_usb_port(_dev) \
@@ -125,6 +127,19 @@ static inline bool hub_is_port_power_switchable(struct usb_hub *hub) 
	return (le16_to_cpu(hcs) & HUB_CHAR_LPSM) < HUB_CHAR_NO_LPSM;

}



static inline int hub_is_superspeed(struct usb_device *hdev)

{

	return hdev->descriptor.bDeviceProtocol == USB_HUB_PR_SS;

}



static inline unsigned hub_power_on_good_delay(struct usb_hub *hub)

{

	unsigned delay = hub->descriptor->bPwrOn2PwrGood * 2;



	/* Wait at least 100 msec for power to become stable */

	return max(delay, 100U);

}



static inline int hub_port_debounce_be_connected(struct usb_hub *hub,

		int port1)

{

drivers/usb/core/port.c

+73 −0
Original line number Diff line number Diff line
@@ -76,6 +76,7 @@ static int usb_port_runtime_resume(struct device *dev) 
	struct usb_device *hdev = to_usb_device(dev->parent->parent);

	struct usb_interface *intf = to_usb_interface(dev->parent);

	struct usb_hub *hub = usb_hub_to_struct_hub(hdev);

	struct usb_port *peer = port_dev->peer;

	int port1 = port_dev->portnum;

	int retval;
@@ -86,10 +87,18 @@ static int usb_port_runtime_resume(struct device *dev) 
		return 0;

	}



	/*

	 * Power on our usb3 peer before this usb2 port to prevent a usb3

	 * device from degrading to its usb2 connection

	 */

	if (!port_dev->is_superspeed && peer)

		pm_runtime_get_sync(&peer->dev);



	usb_autopm_get_interface(intf);

	set_bit(port1, hub->busy_bits);



	retval = usb_hub_set_port_power(hdev, hub, port1, true);

	msleep(hub_power_on_good_delay(hub));

	if (port_dev->child && !retval) {

		/*

		 * Attempt to wait for usb hub port to be reconnected in order
@@ -107,6 +116,7 @@ static int usb_port_runtime_resume(struct device *dev) 


	clear_bit(port1, hub->busy_bits);

	usb_autopm_put_interface(intf);



	return retval;

}
@@ -116,6 +126,7 @@ static int usb_port_runtime_suspend(struct device *dev) 
	struct usb_device *hdev = to_usb_device(dev->parent->parent);

	struct usb_interface *intf = to_usb_interface(dev->parent);

	struct usb_hub *hub = usb_hub_to_struct_hub(hdev);

	struct usb_port *peer = port_dev->peer;

	int port1 = port_dev->portnum;

	int retval;
@@ -135,6 +146,15 @@ static int usb_port_runtime_suspend(struct device *dev) 
	usb_clear_port_feature(hdev, port1,	USB_PORT_FEAT_C_ENABLE);

	clear_bit(port1, hub->busy_bits);

	usb_autopm_put_interface(intf);



	/*

	 * Our peer usb3 port may now be able to suspend, so

	 * asynchronously queue a suspend request to observe that this

	 * usb2 port is now off.

	 */

	if (!port_dev->is_superspeed && peer)

		pm_runtime_put(&peer->dev);



	return retval;

}

#endif
@@ -159,6 +179,7 @@ static struct device_driver usb_port_driver = { 


static int link_peers(struct usb_port *left, struct usb_port *right)

{

	struct usb_port *ss_port, *hs_port;

	int rc;



	if (left->peer == right && right->peer == left)
@@ -184,9 +205,36 @@ static int link_peers(struct usb_port *left, struct usb_port *right) 
		return rc;

	}



	/*

	 * We need to wake the HiSpeed port to make sure we don't race

	 * setting ->peer with usb_port_runtime_suspend().  Otherwise we

	 * may miss a suspend event for the SuperSpeed port.

	 */

	if (left->is_superspeed) {

		ss_port = left;

		WARN_ON(right->is_superspeed);

		hs_port = right;

	} else {

		ss_port = right;

		WARN_ON(!right->is_superspeed);

		hs_port = left;

	}

	pm_runtime_get_sync(&hs_port->dev);



	left->peer = right;

	right->peer = left;



	/*

	 * The SuperSpeed reference is dropped when the HiSpeed port in

	 * this relationship suspends, i.e. when it is safe to allow a

	 * SuperSpeed connection to drop since there is no risk of a

	 * device degrading to its powered-off HiSpeed connection.

	 *

	 * Also, drop the HiSpeed ref taken above.

	 */

	pm_runtime_get_sync(&ss_port->dev);

	pm_runtime_put(&hs_port->dev);



	return 0;

}
@@ -206,14 +254,37 @@ static void link_peers_report(struct usb_port *left, struct usb_port *right) 


static void unlink_peers(struct usb_port *left, struct usb_port *right)

{

	struct usb_port *ss_port, *hs_port;



	WARN(right->peer != left || left->peer != right,

			"%s and %s are not peers?\n",

			dev_name(&left->dev), dev_name(&right->dev));



	/*

	 * We wake the HiSpeed port to make sure we don't race its

	 * usb_port_runtime_resume() event which takes a SuperSpeed ref

	 * when ->peer is !NULL.

	 */

	if (left->is_superspeed) {

		ss_port = left;

		hs_port = right;

	} else {

		ss_port = right;

		hs_port = left;

	}



	pm_runtime_get_sync(&hs_port->dev);



	sysfs_remove_link(&left->dev.kobj, "peer");

	right->peer = NULL;

	sysfs_remove_link(&right->dev.kobj, "peer");

	left->peer = NULL;



	/* Drop the SuperSpeed ref held on behalf of the active HiSpeed port */

	pm_runtime_put(&ss_port->dev);



	/* Drop the ref taken above */

	pm_runtime_put(&hs_port->dev);

}



/*
@@ -325,6 +396,8 @@ int usb_hub_create_port_device(struct usb_hub *hub, int port1) 
	port_dev->dev.groups = port_dev_group;

	port_dev->dev.type = &usb_port_device_type;

	port_dev->dev.driver = &usb_port_driver;

	if (hub_is_superspeed(hub->hdev))

		port_dev->is_superspeed = 1;

	dev_set_name(&port_dev->dev, "%s-port%d", dev_name(&hub->hdev->dev),

			port1);

	retval = device_register(&port_dev->dev);

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