Merge tag 'for-usb-next-2012-05-18' of git://git.kernel.org/pub/scm/linux/kernel/git/sarah/xhci into usb-next

xhci: Link PM and bug fixes for 3.5.

Hi Greg,

Here's the final Link Power Management patches, along with a couple of bug
fixes that have been sitting in my queue. I've fixed all the comments that
Alan and Andiry had on the Link PM patches, so I think they're ready to go.

Sarah Sharp

drivers/bluetooth/ath3k.c

···
 	.probe		= ath3k_probe,
 	.disconnect	= ath3k_disconnect,
 	.id_table	= ath3k_table,
+	.disable_hub_initiated_lpm = 1,
 };
 
 module_usb_driver(ath3k_driver);

drivers/bluetooth/bcm203x.c

···
 	.probe		= bcm203x_probe,
 	.disconnect	= bcm203x_disconnect,
 	.id_table	= bcm203x_table,
+	.disable_hub_initiated_lpm = 1,
 };
 
 module_usb_driver(bcm203x_driver);

drivers/bluetooth/bfusb.c

···
 	.probe		= bfusb_probe,
 	.disconnect	= bfusb_disconnect,
 	.id_table	= bfusb_table,
+	.disable_hub_initiated_lpm = 1,
 };
 
 module_usb_driver(bfusb_driver);

drivers/bluetooth/bpa10x.c

···
 	.probe		= bpa10x_probe,
 	.disconnect	= bpa10x_disconnect,
 	.id_table	= bpa10x_table,
+	.disable_hub_initiated_lpm = 1,
 };
 
 module_usb_driver(bpa10x_driver);

drivers/bluetooth/btusb.c

···
 #endif
 	.id_table	= btusb_table,
 	.supports_autosuspend = 1,
+	.disable_hub_initiated_lpm = 1,
 };
 
 module_usb_driver(btusb_driver);

drivers/isdn/gigaset/bas-gigaset.c

···
 	.reset_resume =	gigaset_post_reset,
 	.pre_reset =	gigaset_pre_reset,
 	.post_reset =	gigaset_post_reset,
+	.disable_hub_initiated_lpm = 1,
 };
 
 /* get message text for usb_submit_urb return code

drivers/isdn/gigaset/usb-gigaset.c

···
 	.reset_resume =	gigaset_resume,
 	.pre_reset =	gigaset_pre_reset,
 	.post_reset =	gigaset_resume,
+	.disable_hub_initiated_lpm = 1,
 };
 
 struct usb_cardstate {

drivers/isdn/hardware/mISDN/hfcsusb.c

···
 	.id_table = hfcsusb_idtab,
 	.probe = hfcsusb_probe,
 	.disconnect = hfcsusb_disconnect,
+	.disable_hub_initiated_lpm = 1,
 };
 
 module_usb_driver(hfcsusb_drv);

drivers/isdn/hisax/hfc_usb.c

···
 	.id_table = hfcusb_idtab,
 	.probe = hfc_usb_probe,
 	.disconnect = hfc_usb_disconnect,
+	.disable_hub_initiated_lpm = 1,
 };
 
 static void __exit

drivers/isdn/hisax/st5481_init.c

···
 	.probe =	probe_st5481,
 	.disconnect =	disconnect_st5481,
 	.id_table =	st5481_ids,
+	.disable_hub_initiated_lpm = 1,
 };
 
 static int __init st5481_usb_init(void)

drivers/net/usb/asix.c

···
 	.resume =	usbnet_resume,
 	.disconnect =	usbnet_disconnect,
 	.supports_autosuspend = 1,
+	.disable_hub_initiated_lpm = 1,
 };
 
 module_usb_driver(asix_driver);

drivers/net/usb/catc.c

···
 	.probe =	catc_probe,
 	.disconnect =	catc_disconnect,
 	.id_table =	catc_id_table,
+	.disable_hub_initiated_lpm = 1,
 };
 
 module_usb_driver(catc_driver);

drivers/net/usb/cdc-phonet.c

···
 	.probe =	usbpn_probe,
 	.disconnect =	usbpn_disconnect,
 	.id_table =	usbpn_ids,
+	.disable_hub_initiated_lpm = 1,
 };
 
 module_usb_driver(usbpn_driver);

drivers/net/usb/cdc_eem.c

···
 	.disconnect =	usbnet_disconnect,
 	.suspend =	usbnet_suspend,
 	.resume =	usbnet_resume,
+	.disable_hub_initiated_lpm = 1,
 };
 
 module_usb_driver(eem_driver);

drivers/net/usb/cdc_ether.c

···
 	.resume =	usbnet_resume,
 	.reset_resume =	usbnet_resume,
 	.supports_autosuspend = 1,
+	.disable_hub_initiated_lpm = 1,
 };
 
 module_usb_driver(cdc_driver);

drivers/net/usb/cdc_ncm.c

···
 	.resume = usbnet_resume,
 	.reset_resume =	usbnet_resume,
 	.supports_autosuspend = 1,
+	.disable_hub_initiated_lpm = 1,
 };
 
 static const struct ethtool_ops cdc_ncm_ethtool_ops = {

drivers/net/usb/cdc_subset.c

···
 	.resume =	usbnet_resume,
 	.disconnect =	usbnet_disconnect,
 	.id_table =	products,
+	.disable_hub_initiated_lpm = 1,
 };
 
 module_usb_driver(cdc_subset_driver);

drivers/net/usb/cx82310_eth.c

···
 	.disconnect	= usbnet_disconnect,
 	.suspend	= usbnet_suspend,
 	.resume		= usbnet_resume,
+	.disable_hub_initiated_lpm = 1,
 };
 
 module_usb_driver(cx82310_driver);

drivers/net/usb/dm9601.c

···
 	.disconnect = usbnet_disconnect,
 	.suspend = usbnet_suspend,
 	.resume = usbnet_resume,
+	.disable_hub_initiated_lpm = 1,
 };
 
 module_usb_driver(dm9601_driver);

drivers/net/usb/gl620a.c

···
 	.disconnect =	usbnet_disconnect,
 	.suspend =	usbnet_suspend,
 	.resume =	usbnet_resume,
+	.disable_hub_initiated_lpm = 1,
 };
 
 module_usb_driver(gl620a_driver);

drivers/net/usb/hso.c

···
 	.resume = hso_resume,
 	.reset_resume = hso_resume,
 	.supports_autosuspend = 1,
+	.disable_hub_initiated_lpm = 1,
 };
 
 static int __init hso_init(void)

drivers/net/usb/int51x1.c

···
 	.disconnect = usbnet_disconnect,
 	.suspend    = usbnet_suspend,
 	.resume     = usbnet_resume,
+	.disable_hub_initiated_lpm = 1,
 };
 
 module_usb_driver(int51x1_driver);

drivers/net/usb/ipheth.c

···
 	.probe =	ipheth_probe,
 	.disconnect =	ipheth_disconnect,
 	.id_table =	ipheth_table,
+	.disable_hub_initiated_lpm = 1,
 };
 
 module_usb_driver(ipheth_driver);

drivers/net/usb/kalmia.c

···
 	.probe = usbnet_probe,
 	.disconnect = usbnet_disconnect,
 	.suspend = usbnet_suspend,
-	.resume = usbnet_resume
+	.resume = usbnet_resume,
+	.disable_hub_initiated_lpm = 1,
 };
 
 module_usb_driver(kalmia_driver);

drivers/net/usb/kaweth.c

···
 	.resume =	kaweth_resume,
 	.id_table =     usb_klsi_table,
 	.supports_autosuspend =	1,
+	.disable_hub_initiated_lpm = 1,
 };
 
 typedef __u8 eth_addr_t[6];

drivers/net/usb/lg-vl600.c

···
 	.disconnect	= usbnet_disconnect,
 	.suspend	= usbnet_suspend,
 	.resume		= usbnet_resume,
+	.disable_hub_initiated_lpm = 1,
 };
 
 module_usb_driver(lg_vl600_driver);

drivers/net/usb/mcs7830.c

···
 	.suspend = usbnet_suspend,
 	.resume = usbnet_resume,
 	.reset_resume = mcs7830_reset_resume,
+	.disable_hub_initiated_lpm = 1,
 };
 
 module_usb_driver(mcs7830_driver);

drivers/net/usb/net1080.c

···
 	.disconnect =	usbnet_disconnect,
 	.suspend =	usbnet_suspend,
 	.resume =	usbnet_resume,
+	.disable_hub_initiated_lpm = 1,
 };
 
 module_usb_driver(net1080_driver);

drivers/net/usb/pegasus.c

···
 	.id_table = pegasus_ids,
 	.suspend = pegasus_suspend,
 	.resume = pegasus_resume,
+	.disable_hub_initiated_lpm = 1,
 };
 
 static void __init parse_id(char *id)

drivers/net/usb/plusb.c

···
 	.disconnect =	usbnet_disconnect,
 	.suspend =	usbnet_suspend,
 	.resume =	usbnet_resume,
+	.disable_hub_initiated_lpm = 1,
 };
 
 module_usb_driver(plusb_driver);

drivers/net/usb/qmi_wwan.c

···
 	.resume		      =	qmi_wwan_resume,
 	.reset_resume         = qmi_wwan_resume,
 	.supports_autosuspend = 1,
+	.disable_hub_initiated_lpm = 1,
 };
 
 static int __init qmi_wwan_init(void)

drivers/net/usb/rndis_host.c

···
 	.disconnect =	usbnet_disconnect,
 	.suspend =	usbnet_suspend,
 	.resume =	usbnet_resume,
+	.disable_hub_initiated_lpm = 1,
 };
 
 module_usb_driver(rndis_driver);

drivers/net/usb/rtl8150.c

···
 	.disconnect	= rtl8150_disconnect,
 	.id_table	= rtl8150_table,
 	.suspend	= rtl8150_suspend,
-	.resume		= rtl8150_resume
+	.resume		= rtl8150_resume,
+	.disable_hub_initiated_lpm = 1,
 };
 
 module_usb_driver(rtl8150_driver);

drivers/net/usb/sierra_net.c

···
 	.suspend = usbnet_suspend,
 	.resume = usbnet_resume,
 	.no_dynamic_id = 1,
+	.disable_hub_initiated_lpm = 1,
 };
 
 module_usb_driver(sierra_net_driver);

drivers/net/usb/smsc75xx.c

···
 	.suspend	= usbnet_suspend,
 	.resume		= usbnet_resume,
 	.disconnect	= usbnet_disconnect,
+	.disable_hub_initiated_lpm = 1,
 };
 
 module_usb_driver(smsc75xx_driver);

drivers/net/usb/smsc95xx.c

···
 	.suspend	= usbnet_suspend,
 	.resume		= usbnet_resume,
 	.disconnect	= usbnet_disconnect,
+	.disable_hub_initiated_lpm = 1,
 };
 
 module_usb_driver(smsc95xx_driver);

drivers/net/usb/zaurus.c

···
 	.disconnect =	usbnet_disconnect,
 	.suspend =	usbnet_suspend,
 	.resume =	usbnet_resume,
+	.disable_hub_initiated_lpm = 1,
 };
 
 module_usb_driver(zaurus_driver);

drivers/net/wireless/at76c50x-usb.c

···
 	.probe = at76_probe,
 	.disconnect = at76_disconnect,
 	.id_table = dev_table,
+	.disable_hub_initiated_lpm = 1,
 };
 
 static int __init at76_mod_init(void)

drivers/net/wireless/ath/ath6kl/usb.c

···
 	.probe = ath6kl_usb_probe,
 	.disconnect = ath6kl_usb_remove,
 	.id_table = ath6kl_usb_ids,
+	.disable_hub_initiated_lpm = 1,
 };
 
 static int ath6kl_usb_init(void)

drivers/net/wireless/ath/ath9k/hif_usb.c

···
 #endif
 	.id_table = ath9k_hif_usb_ids,
 	.soft_unbind = 1,
+	.disable_hub_initiated_lpm = 1,
 };
 
 int ath9k_hif_usb_init(void)

drivers/net/wireless/ath/carl9170/usb.c

···
 	.resume = carl9170_usb_resume,
 	.reset_resume = carl9170_usb_resume,
 #endif /* CONFIG_PM */
+	.disable_hub_initiated_lpm = 1,
 };
 
 module_usb_driver(carl9170_driver);

drivers/net/wireless/brcm80211/brcmfmac/usb.c

···
 	.suspend = brcmf_usb_suspend,
 	.resume = brcmf_usb_resume,
 	.supports_autosuspend = 1
+	.disable_hub_initiated_lpm = 1,
 };
 
 void brcmf_usb_exit(void)

drivers/net/wireless/libertas/if_usb.c

···
 	.suspend = if_usb_suspend,
 	.resume = if_usb_resume,
 	.reset_resume = if_usb_resume,
+	.disable_hub_initiated_lpm = 1,
 };
 
 module_usb_driver(if_usb_driver);

drivers/net/wireless/libertas_tf/if_usb.c

···
 	.id_table = if_usb_table,
 	.suspend = if_usb_suspend,
 	.resume = if_usb_resume,
+	.disable_hub_initiated_lpm = 1,
 };
 
 module_usb_driver(if_usb_driver);

drivers/net/wireless/orinoco/orinoco_usb.c

···
 	.probe = ezusb_probe,
 	.disconnect = ezusb_disconnect,
 	.id_table = ezusb_table,
+	.disable_hub_initiated_lpm = 1,
 };
 
 module_usb_driver(orinoco_driver);

drivers/net/wireless/p54/p54usb.c

···
 	.reset_resume = p54u_resume,
 #endif /* CONFIG_PM */
 	.soft_unbind = 1,
+	.disable_hub_initiated_lpm = 1,
 };
 
 module_usb_driver(p54u_driver);

drivers/net/wireless/rndis_wlan.c

···
 	.disconnect =	usbnet_disconnect,
 	.suspend =	usbnet_suspend,
 	.resume =	usbnet_resume,
+	.disable_hub_initiated_lpm = 1,
 };
 
 module_usb_driver(rndis_wlan_driver);

drivers/net/wireless/rt2x00/rt2500usb.c

···
 	.disconnect	= rt2x00usb_disconnect,
 	.suspend	= rt2x00usb_suspend,
 	.resume		= rt2x00usb_resume,
+	.disable_hub_initiated_lpm = 1,
 };
 
 module_usb_driver(rt2500usb_driver);

drivers/net/wireless/rt2x00/rt2800usb.c

···
 	.disconnect	= rt2x00usb_disconnect,
 	.suspend	= rt2x00usb_suspend,
 	.resume		= rt2x00usb_resume,
+	.disable_hub_initiated_lpm = 1,
 };
 
 module_usb_driver(rt2800usb_driver);

drivers/net/wireless/rt2x00/rt73usb.c

···
 	.disconnect	= rt2x00usb_disconnect,
 	.suspend	= rt2x00usb_suspend,
 	.resume		= rt2x00usb_resume,
+	.disable_hub_initiated_lpm = 1,
 };
 
 module_usb_driver(rt73usb_driver);

drivers/net/wireless/rtl818x/rtl8187/dev.c

···
 	.id_table	= rtl8187_table,
 	.probe		= rtl8187_probe,
 	.disconnect	= __devexit_p(rtl8187_disconnect),
+	.disable_hub_initiated_lpm = 1,
 };
 
 module_usb_driver(rtl8187_driver);

drivers/net/wireless/rtlwifi/rtl8192cu/sw.c

···
 #ifdef CONFIG_AUTOSUSPEND
 	.supports_autosuspend = 1,
 #endif
+	.disable_hub_initiated_lpm = 1,
 };
 
 module_usb_driver(rtl8192cu_driver);

drivers/net/wireless/zd1201.c

···
 	.id_table = zd1201_table,
 	.suspend = zd1201_suspend,
 	.resume = zd1201_resume,
+	.disable_hub_initiated_lpm = 1,
 };
 
 module_usb_driver(zd1201_usb);

drivers/net/wireless/zd1211rw/zd_usb.c

···
 	.disconnect	= disconnect,
 	.pre_reset	= pre_reset,
 	.post_reset	= post_reset,
+	.disable_hub_initiated_lpm = 1,
 };
 
 struct workqueue_struct *zd_workqueue;

drivers/usb/class/cdc-acm.c

···
 #ifdef CONFIG_PM
 	.supports_autosuspend = 1,
 #endif
+	.disable_hub_initiated_lpm = 1,
 };
 
 /*

drivers/usb/class/cdc-wdm.c

···
 	.post_reset =	wdm_post_reset,
 	.id_table =	wdm_ids,
 	.supports_autosuspend = 1,
+	.disable_hub_initiated_lpm = 1,
 };
 
 module_usb_driver(wdm_driver);

drivers/usb/core/driver.c

···
 	struct usb_device *udev = interface_to_usbdev(intf);
 	const struct usb_device_id *id;
 	int error = -ENODEV;
+	int lpm_disable_error;
 
 	dev_dbg(dev, "%s\n", __func__);
 
···
 	if (driver->supports_autosuspend)
 		pm_runtime_enable(dev);
 
+	/* If the new driver doesn't allow hub-initiated LPM, and we can't
+	 * disable hub-initiated LPM, then fail the probe.
+	 *
+	 * Otherwise, leaving LPM enabled should be harmless, because the
+	 * endpoint intervals should remain the same, and the U1/U2 timeouts
+	 * should remain the same.
+	 *
+	 * If we need to install alt setting 0 before probe, or another alt
+	 * setting during probe, that should also be fine.  usb_set_interface()
+	 * will attempt to disable LPM, and fail if it can't disable it.
+	 */
+	lpm_disable_error = usb_unlocked_disable_lpm(udev);
+	if (lpm_disable_error && driver->disable_hub_initiated_lpm) {
+		dev_err(&intf->dev, "%s Failed to disable LPM for driver %s\n.",
+				__func__, driver->name);
+		error = lpm_disable_error;
+		goto err;
+	}
+
 	/* Carry out a deferred switch to altsetting 0 */
 	if (intf->needs_altsetting0) {
 		error = usb_set_interface(udev, intf->altsetting[0].
···
 		goto err;
 
 	intf->condition = USB_INTERFACE_BOUND;
+
+	/* If the LPM disable succeeded, balance the ref counts. */
+	if (!lpm_disable_error)
+		usb_unlocked_enable_lpm(udev);
+
 	usb_autosuspend_device(udev);
 	return error;
 
···
 	struct usb_driver *driver = to_usb_driver(dev->driver);
 	struct usb_interface *intf = to_usb_interface(dev);
 	struct usb_device *udev;
-	int error, r;
+	int error, r, lpm_disable_error;
 
 	intf->condition = USB_INTERFACE_UNBINDING;
 
 	/* Autoresume for set_interface call below */
 	udev = interface_to_usbdev(intf);
 	error = usb_autoresume_device(udev);
+
+	/* Hub-initiated LPM policy may change, so attempt to disable LPM until
+	 * the driver is unbound.  If LPM isn't disabled, that's fine because it
+	 * wouldn't be enabled unless all the bound interfaces supported
+	 * hub-initiated LPM.
+	 */
+	lpm_disable_error = usb_unlocked_disable_lpm(udev);
 
 	/* Terminate all URBs for this interface unless the driver
 	 * supports "soft" unbinding.
···
 
 	intf->condition = USB_INTERFACE_UNBOUND;
 	intf->needs_remote_wakeup = 0;
+
+	/* Attempt to re-enable USB3 LPM, if the disable succeeded. */
+	if (!lpm_disable_error)
+		usb_unlocked_enable_lpm(udev);
 
 	/* Unbound interfaces are always runtime-PM-disabled and -suspended */
 	if (driver->supports_autosuspend)
···
 				struct usb_interface *iface, void *priv)
 {
 	struct device *dev = &iface->dev;
+	struct usb_device *udev;
 	int retval = 0;
+	int lpm_disable_error;
 
 	if (dev->driver)
 		return -EBUSY;
+
+	udev = interface_to_usbdev(iface);
 
 	dev->driver = &driver->drvwrap.driver;
 	usb_set_intfdata(iface, priv);
 	iface->needs_binding = 0;
 
 	iface->condition = USB_INTERFACE_BOUND;
+
+	/* Disable LPM until this driver is bound. */
+	lpm_disable_error = usb_unlocked_disable_lpm(udev);
+	if (lpm_disable_error && driver->disable_hub_initiated_lpm) {
+		dev_err(&iface->dev, "%s Failed to disable LPM for driver %s\n.",
+				__func__, driver->name);
+		return -ENOMEM;
+	}
 
 	/* Claimed interfaces are initially inactive (suspended) and
 	 * runtime-PM-enabled, but only if the driver has autosuspend
···
 	 */
 	if (device_is_registered(dev))
 		retval = device_bind_driver(dev);
+
+	/* Attempt to re-enable USB3 LPM, if the disable was successful. */
+	if (!lpm_disable_error)
+		usb_unlocked_enable_lpm(udev);
 
 	return retval;
 }

drivers/usb/core/hcd.c

···
 				dev_name(&usb_dev->dev), retval);
 		return (retval < 0) ? retval : -EMSGSIZE;
 	}
+	if (usb_dev->speed == USB_SPEED_SUPER) {
+		retval = usb_get_bos_descriptor(usb_dev);
+		if (retval < 0) {
+			mutex_unlock(&usb_bus_list_lock);
+			dev_dbg(parent_dev, "can't read %s bos descriptor %d\n",
+					dev_name(&usb_dev->dev), retval);
+			return retval;
+		}
+	}
 
 	retval = usb_new_device (usb_dev);
 	if (retval) {

drivers/usb/core/hub.c

···
 	return usb_get_intfdata(hdev->actconfig->interface[0]);
 }
 
+static int usb_device_supports_lpm(struct usb_device *udev)
+{
+	/* USB 2.1 (and greater) devices indicate LPM support through
+	 * their USB 2.0 Extended Capabilities BOS descriptor.
+	 */
+	if (udev->speed == USB_SPEED_HIGH) {
+		if (udev->bos->ext_cap &&
+			(USB_LPM_SUPPORT &
+			 le32_to_cpu(udev->bos->ext_cap->bmAttributes)))
+			return 1;
+		return 0;
+	}
+
+	/* All USB 3.0 must support LPM, but we need their max exit latency
+	 * information from the SuperSpeed Extended Capabilities BOS descriptor.
+	 */
+	if (!udev->bos->ss_cap) {
+		dev_warn(&udev->dev, "No LPM exit latency info found.  "
+				"Power management will be impacted.\n");
+		return 0;
+	}
+	if (udev->parent->lpm_capable)
+		return 1;
+
+	dev_warn(&udev->dev, "Parent hub missing LPM exit latency info.  "
+			"Power management will be impacted.\n");
+	return 0;
+}
+
+/*
+ * Set the Maximum Exit Latency (MEL) for the host to initiate a transition from
+ * either U1 or U2.
+ */
+static void usb_set_lpm_mel(struct usb_device *udev,
+		struct usb3_lpm_parameters *udev_lpm_params,
+		unsigned int udev_exit_latency,
+		struct usb_hub *hub,
+		struct usb3_lpm_parameters *hub_lpm_params,
+		unsigned int hub_exit_latency)
+{
+	unsigned int total_mel;
+	unsigned int device_mel;
+	unsigned int hub_mel;
+
+	/*
+	 * Calculate the time it takes to transition all links from the roothub
+	 * to the parent hub into U0.  The parent hub must then decode the
+	 * packet (hub header decode latency) to figure out which port it was
+	 * bound for.
+	 *
+	 * The Hub Header decode latency is expressed in 0.1us intervals (0x1
+	 * means 0.1us).  Multiply that by 100 to get nanoseconds.
+	 */
+	total_mel = hub_lpm_params->mel +
+		(hub->descriptor->u.ss.bHubHdrDecLat * 100);
+
+	/*
+	 * How long will it take to transition the downstream hub's port into
+	 * U0?  The greater of either the hub exit latency or the device exit
+	 * latency.
+	 *
+	 * The BOS U1/U2 exit latencies are expressed in 1us intervals.
+	 * Multiply that by 1000 to get nanoseconds.
+	 */
+	device_mel = udev_exit_latency * 1000;
+	hub_mel = hub_exit_latency * 1000;
+	if (device_mel > hub_mel)
+		total_mel += device_mel;
+	else
+		total_mel += hub_mel;
+
+	udev_lpm_params->mel = total_mel;
+}
+
+/*
+ * Set the maximum Device to Host Exit Latency (PEL) for the device to initiate
+ * a transition from either U1 or U2.
+ */
+static void usb_set_lpm_pel(struct usb_device *udev,
+		struct usb3_lpm_parameters *udev_lpm_params,
+		unsigned int udev_exit_latency,
+		struct usb_hub *hub,
+		struct usb3_lpm_parameters *hub_lpm_params,
+		unsigned int hub_exit_latency,
+		unsigned int port_to_port_exit_latency)
+{
+	unsigned int first_link_pel;
+	unsigned int hub_pel;
+
+	/*
+	 * First, the device sends an LFPS to transition the link between the
+	 * device and the parent hub into U0.  The exit latency is the bigger of
+	 * the device exit latency or the hub exit latency.
+	 */
+	if (udev_exit_latency > hub_exit_latency)
+		first_link_pel = udev_exit_latency * 1000;
+	else
+		first_link_pel = hub_exit_latency * 1000;
+
+	/*
+	 * When the hub starts to receive the LFPS, there is a slight delay for
+	 * it to figure out that one of the ports is sending an LFPS.  Then it
+	 * will forward the LFPS to its upstream link.  The exit latency is the
+	 * delay, plus the PEL that we calculated for this hub.
+	 */
+	hub_pel = port_to_port_exit_latency * 1000 + hub_lpm_params->pel;
+
+	/*
+	 * According to figure C-7 in the USB 3.0 spec, the PEL for this device
+	 * is the greater of the two exit latencies.
+	 */
+	if (first_link_pel > hub_pel)
+		udev_lpm_params->pel = first_link_pel;
+	else
+		udev_lpm_params->pel = hub_pel;
+}
+
+/*
+ * Set the System Exit Latency (SEL) to indicate the total worst-case time from
+ * when a device initiates a transition to U0, until when it will receive the
+ * first packet from the host controller.
+ *
+ * Section C.1.5.1 describes the four components to this:
+ *  - t1: device PEL
+ *  - t2: time for the ERDY to make it from the device to the host.
+ *  - t3: a host-specific delay to process the ERDY.
+ *  - t4: time for the packet to make it from the host to the device.
+ *
+ * t3 is specific to both the xHCI host and the platform the host is integrated
+ * into.  The Intel HW folks have said it's negligible, FIXME if a different
+ * vendor says otherwise.
+ */
+static void usb_set_lpm_sel(struct usb_device *udev,
+		struct usb3_lpm_parameters *udev_lpm_params)
+{
+	struct usb_device *parent;
+	unsigned int num_hubs;
+	unsigned int total_sel;
+
+	/* t1 = device PEL */
+	total_sel = udev_lpm_params->pel;
+	/* How many external hubs are in between the device & the root port. */
+	for (parent = udev->parent, num_hubs = 0; parent->parent;
+			parent = parent->parent)
+		num_hubs++;
+	/* t2 = 2.1us + 250ns * (num_hubs - 1) */
+	if (num_hubs > 0)
+		total_sel += 2100 + 250 * (num_hubs - 1);
+
+	/* t4 = 250ns * num_hubs */
+	total_sel += 250 * num_hubs;
+
+	udev_lpm_params->sel = total_sel;
+}
+
+static void usb_set_lpm_parameters(struct usb_device *udev)
+{
+	struct usb_hub *hub;
+	unsigned int port_to_port_delay;
+	unsigned int udev_u1_del;
+	unsigned int udev_u2_del;
+	unsigned int hub_u1_del;
+	unsigned int hub_u2_del;
+
+	if (!udev->lpm_capable || udev->speed != USB_SPEED_SUPER)
+		return;
+
+	hub = hdev_to_hub(udev->parent);
+	/* It doesn't take time to transition the roothub into U0, since it
+	 * doesn't have an upstream link.
+	 */
+	if (!hub)
+		return;
+
+	udev_u1_del = udev->bos->ss_cap->bU1devExitLat;
+	udev_u2_del = udev->bos->ss_cap->bU2DevExitLat;
+	hub_u1_del = udev->parent->bos->ss_cap->bU1devExitLat;
+	hub_u2_del = udev->parent->bos->ss_cap->bU2DevExitLat;
+
+	usb_set_lpm_mel(udev, &udev->u1_params, udev_u1_del,
+			hub, &udev->parent->u1_params, hub_u1_del);
+
+	usb_set_lpm_mel(udev, &udev->u2_params, udev_u2_del,
+			hub, &udev->parent->u2_params, hub_u2_del);
+
+	/*
+	 * Appendix C, section C.2.2.2, says that there is a slight delay from
+	 * when the parent hub notices the downstream port is trying to
+	 * transition to U0 to when the hub initiates a U0 transition on its
+	 * upstream port.  The section says the delays are tPort2PortU1EL and
+	 * tPort2PortU2EL, but it doesn't define what they are.
+	 *
+	 * The hub chapter, sections 10.4.2.4 and 10.4.2.5 seem to be talking
+	 * about the same delays.  Use the maximum delay calculations from those
+	 * sections.  For U1, it's tHubPort2PortExitLat, which is 1us max.  For
+	 * U2, it's tHubPort2PortExitLat + U2DevExitLat - U1DevExitLat.  I
+	 * assume the device exit latencies they are talking about are the hub
+	 * exit latencies.
+	 *
+	 * What do we do if the U2 exit latency is less than the U1 exit
+	 * latency?  It's possible, although not likely...
+	 */
+	port_to_port_delay = 1;
+
+	usb_set_lpm_pel(udev, &udev->u1_params, udev_u1_del,
+			hub, &udev->parent->u1_params, hub_u1_del,
+			port_to_port_delay);
+
+	if (hub_u2_del > hub_u1_del)
+		port_to_port_delay = 1 + hub_u2_del - hub_u1_del;
+	else
+		port_to_port_delay = 1 + hub_u1_del;
+
+	usb_set_lpm_pel(udev, &udev->u2_params, udev_u2_del,
+			hub, &udev->parent->u2_params, hub_u2_del,
+			port_to_port_delay);
+
+	/* Now that we've got PEL, calculate SEL. */
+	usb_set_lpm_sel(udev, &udev->u1_params);
+	usb_set_lpm_sel(udev, &udev->u2_params);
+}
+
 /* USB 2.0 spec Section 11.24.4.5 */
 static int get_hub_descriptor(struct usb_device *hdev, void *data)
 {
···
 	if (udev->usb2_hw_lpm_enabled == 1)
 		usb_set_usb2_hardware_lpm(udev, 0);
 
+	if (usb_unlocked_disable_lpm(udev)) {
+		dev_err(&udev->dev, "%s Failed to disable LPM before suspend\n.",
+				__func__);
+		return -ENOMEM;
+	}
+
 	/* see 7.1.7.6 */
 	if (hub_is_superspeed(hub->hdev))
 		status = set_port_feature(hub->hdev,
···
 				USB_DEVICE_REMOTE_WAKEUP, 0,
 				NULL, 0,
 				USB_CTRL_SET_TIMEOUT);
+
+		/* Try to enable USB2 hardware LPM again */
+		if (udev->usb2_hw_lpm_capable == 1)
+			usb_set_usb2_hardware_lpm(udev, 1);
+
+		/* Try to enable USB3 LPM again */
+		usb_unlocked_enable_lpm(udev);
 
 		/* System sleep transitions should never fail */
 		if (!PMSG_IS_AUTO(msg))
···
 		/* Try to enable USB2 hardware LPM */
 		if (udev->usb2_hw_lpm_capable == 1)
 			usb_set_usb2_hardware_lpm(udev, 1);
+
+		/* Try to enable USB3 LPM */
+		usb_unlocked_enable_lpm(udev);
 	}
 
 	return status;
···
 }
 EXPORT_SYMBOL_GPL(usb_root_hub_lost_power);
 
+static const char * const usb3_lpm_names[]  = {
+	"U0",
+	"U1",
+	"U2",
+	"U3",
+};
+
+/*
+ * Send a Set SEL control transfer to the device, prior to enabling
+ * device-initiated U1 or U2.  This lets the device know the exit latencies from
+ * the time the device initiates a U1 or U2 exit, to the time it will receive a
+ * packet from the host.
+ *
+ * This function will fail if the SEL or PEL values for udev are greater than
+ * the maximum allowed values for the link state to be enabled.
+ */
+static int usb_req_set_sel(struct usb_device *udev, enum usb3_link_state state)
+{
+	struct usb_set_sel_req *sel_values;
+	unsigned long long u1_sel;
+	unsigned long long u1_pel;
+	unsigned long long u2_sel;
+	unsigned long long u2_pel;
+	int ret;
+
+	/* Convert SEL and PEL stored in ns to us */
+	u1_sel = DIV_ROUND_UP(udev->u1_params.sel, 1000);
+	u1_pel = DIV_ROUND_UP(udev->u1_params.pel, 1000);
+	u2_sel = DIV_ROUND_UP(udev->u2_params.sel, 1000);
+	u2_pel = DIV_ROUND_UP(udev->u2_params.pel, 1000);
+
+	/*
+	 * Make sure that the calculated SEL and PEL values for the link
+	 * state we're enabling aren't bigger than the max SEL/PEL
+	 * value that will fit in the SET SEL control transfer.
+	 * Otherwise the device would get an incorrect idea of the exit
+	 * latency for the link state, and could start a device-initiated
+	 * U1/U2 when the exit latencies are too high.
+	 */
+	if ((state == USB3_LPM_U1 &&
+				(u1_sel > USB3_LPM_MAX_U1_SEL_PEL ||
+				 u1_pel > USB3_LPM_MAX_U1_SEL_PEL)) ||
+			(state == USB3_LPM_U2 &&
+			 (u2_sel > USB3_LPM_MAX_U2_SEL_PEL ||
+			  u2_pel > USB3_LPM_MAX_U2_SEL_PEL))) {
+		dev_dbg(&udev->dev, "Device-initiated %s disabled due "
+				"to long SEL %llu ms or PEL %llu ms\n",
+				usb3_lpm_names[state], u1_sel, u1_pel);
+		return -EINVAL;
+	}
+
+	/*
+	 * If we're enabling device-initiated LPM for one link state,
+	 * but the other link state has a too high SEL or PEL value,
+	 * just set those values to the max in the Set SEL request.
+	 */
+	if (u1_sel > USB3_LPM_MAX_U1_SEL_PEL)
+		u1_sel = USB3_LPM_MAX_U1_SEL_PEL;
+
+	if (u1_pel > USB3_LPM_MAX_U1_SEL_PEL)
+		u1_pel = USB3_LPM_MAX_U1_SEL_PEL;
+
+	if (u2_sel > USB3_LPM_MAX_U2_SEL_PEL)
+		u2_sel = USB3_LPM_MAX_U2_SEL_PEL;
+
+	if (u2_pel > USB3_LPM_MAX_U2_SEL_PEL)
+		u2_pel = USB3_LPM_MAX_U2_SEL_PEL;
+
+	/*
+	 * usb_enable_lpm() can be called as part of a failed device reset,
+	 * which may be initiated by an error path of a mass storage driver.
+	 * Therefore, use GFP_NOIO.
+	 */
+	sel_values = kmalloc(sizeof *(sel_values), GFP_NOIO);
+	if (!sel_values)
+		return -ENOMEM;
+
+	sel_values->u1_sel = u1_sel;
+	sel_values->u1_pel = u1_pel;
+	sel_values->u2_sel = cpu_to_le16(u2_sel);
+	sel_values->u2_pel = cpu_to_le16(u2_pel);
+
+	ret = usb_control_msg(udev, usb_sndctrlpipe(udev, 0),
+			USB_REQ_SET_SEL,
+			USB_RECIP_DEVICE,
+			0, 0,
+			sel_values, sizeof *(sel_values),
+			USB_CTRL_SET_TIMEOUT);
+	kfree(sel_values);
+	return ret;
+}
+
+/*
+ * Enable or disable device-initiated U1 or U2 transitions.
+ */
+static int usb_set_device_initiated_lpm(struct usb_device *udev,
+		enum usb3_link_state state, bool enable)
+{
+	int ret;
+	int feature;
+
+	switch (state) {
+	case USB3_LPM_U1:
+		feature = USB_DEVICE_U1_ENABLE;
+		break;
+	case USB3_LPM_U2:
+		feature = USB_DEVICE_U2_ENABLE;
+		break;
+	default:
+		dev_warn(&udev->dev, "%s: Can't %s non-U1 or U2 state.\n",
+				__func__, enable ? "enable" : "disable");
+		return -EINVAL;
+	}
+
+	if (udev->state != USB_STATE_CONFIGURED) {
+		dev_dbg(&udev->dev, "%s: Can't %s %s state "
+				"for unconfigured device.\n",
+				__func__, enable ? "enable" : "disable",
+				usb3_lpm_names[state]);
+		return 0;
+	}
+
+	if (enable) {
+		/*
+		 * First, let the device know about the exit latencies
+		 * associated with the link state we're about to enable.
+		 */
+		ret = usb_req_set_sel(udev, state);
+		if (ret < 0) {
+			dev_warn(&udev->dev, "Set SEL for device-initiated "
+					"%s failed.\n", usb3_lpm_names[state]);
+			return -EBUSY;
+		}
+		/*
+		 * Now send the control transfer to enable device-initiated LPM
+		 * for either U1 or U2.
+		 */
+		ret = usb_control_msg(udev, usb_sndctrlpipe(udev, 0),
+				USB_REQ_SET_FEATURE,
+				USB_RECIP_DEVICE,
+				feature,
+				0, NULL, 0,
+				USB_CTRL_SET_TIMEOUT);
+	} else {
+		ret = usb_control_msg(udev, usb_sndctrlpipe(udev, 0),
+				USB_REQ_CLEAR_FEATURE,
+				USB_RECIP_DEVICE,
+				feature,
+				0, NULL, 0,
+				USB_CTRL_SET_TIMEOUT);
+	}
+	if (ret < 0) {
+		dev_warn(&udev->dev, "%s of device-initiated %s failed.\n",
+				enable ? "Enable" : "Disable",
+				usb3_lpm_names[state]);
+		return -EBUSY;
+	}
+	return 0;
+}
+
+static int usb_set_lpm_timeout(struct usb_device *udev,
+		enum usb3_link_state state, int timeout)
+{
+	int ret;
+	int feature;
+
+	switch (state) {
+	case USB3_LPM_U1:
+		feature = USB_PORT_FEAT_U1_TIMEOUT;
+		break;
+	case USB3_LPM_U2:
+		feature = USB_PORT_FEAT_U2_TIMEOUT;
+		break;
+	default:
+		dev_warn(&udev->dev, "%s: Can't set timeout for non-U1 or U2 state.\n",
+				__func__);
+		return -EINVAL;
+	}
+
+	if (state == USB3_LPM_U1 && timeout > USB3_LPM_U1_MAX_TIMEOUT &&
+			timeout != USB3_LPM_DEVICE_INITIATED) {
+		dev_warn(&udev->dev, "Failed to set %s timeout to 0x%x, "
+				"which is a reserved value.\n",
+				usb3_lpm_names[state], timeout);
+		return -EINVAL;
+	}
+
+	ret = set_port_feature(udev->parent,
+			USB_PORT_LPM_TIMEOUT(timeout) | udev->portnum,
+			feature);
+	if (ret < 0) {
+		dev_warn(&udev->dev, "Failed to set %s timeout to 0x%x,"
+				"error code %i\n", usb3_lpm_names[state],
+				timeout, ret);
+		return -EBUSY;
+	}
+	if (state == USB3_LPM_U1)
+		udev->u1_params.timeout = timeout;
+	else
+		udev->u2_params.timeout = timeout;
+	return 0;
+}
+
+/*
+ * Enable the hub-initiated U1/U2 idle timeouts, and enable device-initiated
+ * U1/U2 entry.
+ *
+ * We will attempt to enable U1 or U2, but there are no guarantees that the
+ * control transfers to set the hub timeout or enable device-initiated U1/U2
+ * will be successful.
+ *
+ * If we cannot set the parent hub U1/U2 timeout, we attempt to let the xHCI
+ * driver know about it.  If that call fails, it should be harmless, and just
+ * take up more slightly more bus bandwidth for unnecessary U1/U2 exit latency.
+ */
+static void usb_enable_link_state(struct usb_hcd *hcd, struct usb_device *udev,
+		enum usb3_link_state state)
+{
+	int timeout;
+
+	/* We allow the host controller to set the U1/U2 timeout internally
+	 * first, so that it can change its schedule to account for the
+	 * additional latency to send data to a device in a lower power
+	 * link state.
+	 */
+	timeout = hcd->driver->enable_usb3_lpm_timeout(hcd, udev, state);
+
+	/* xHCI host controller doesn't want to enable this LPM state. */
+	if (timeout == 0)
+		return;
+
+	if (timeout < 0) {
+		dev_warn(&udev->dev, "Could not enable %s link state, "
+				"xHCI error %i.\n", usb3_lpm_names[state],
+				timeout);
+		return;
+	}
+
+	if (usb_set_lpm_timeout(udev, state, timeout))
+		/* If we can't set the parent hub U1/U2 timeout,
+		 * device-initiated LPM won't be allowed either, so let the xHCI
+		 * host know that this link state won't be enabled.
+		 */
+		hcd->driver->disable_usb3_lpm_timeout(hcd, udev, state);
+
+	/* Only a configured device will accept the Set Feature U1/U2_ENABLE */
+	else if (udev->actconfig)
+		usb_set_device_initiated_lpm(udev, state, true);
+
+}
+
+/*
+ * Disable the hub-initiated U1/U2 idle timeouts, and disable device-initiated
+ * U1/U2 entry.
+ *
+ * If this function returns -EBUSY, the parent hub will still allow U1/U2 entry.
+ * If zero is returned, the parent will not allow the link to go into U1/U2.
+ *
+ * If zero is returned, device-initiated U1/U2 entry may still be enabled, but
+ * it won't have an effect on the bus link state because the parent hub will
+ * still disallow device-initiated U1/U2 entry.
+ *
+ * If zero is returned, the xHCI host controller may still think U1/U2 entry is
+ * possible.  The result will be slightly more bus bandwidth will be taken up
+ * (to account for U1/U2 exit latency), but it should be harmless.
+ */
+static int usb_disable_link_state(struct usb_hcd *hcd, struct usb_device *udev,
+		enum usb3_link_state state)
+{
+	int feature;
+
+	switch (state) {
+	case USB3_LPM_U1:
+		feature = USB_PORT_FEAT_U1_TIMEOUT;
+		break;
+	case USB3_LPM_U2:
+		feature = USB_PORT_FEAT_U2_TIMEOUT;
+		break;
+	default:
+		dev_warn(&udev->dev, "%s: Can't disable non-U1 or U2 state.\n",
+				__func__);
+		return -EINVAL;
+	}
+
+	if (usb_set_lpm_timeout(udev, state, 0))
+		return -EBUSY;
+
+	usb_set_device_initiated_lpm(udev, state, false);
+
+	if (hcd->driver->disable_usb3_lpm_timeout(hcd, udev, state))
+		dev_warn(&udev->dev, "Could not disable xHCI %s timeout, "
+				"bus schedule bandwidth may be impacted.\n",
+				usb3_lpm_names[state]);
+	return 0;
+}
+
+/*
+ * Disable hub-initiated and device-initiated U1 and U2 entry.
+ * Caller must own the bandwidth_mutex.
+ *
+ * This will call usb_enable_lpm() on failure, which will decrement
+ * lpm_disable_count, and will re-enable LPM if lpm_disable_count reaches zero.
+ */
+int usb_disable_lpm(struct usb_device *udev)
+{
+	struct usb_hcd *hcd;
+
+	if (!udev || !udev->parent ||
+			udev->speed != USB_SPEED_SUPER ||
+			!udev->lpm_capable)
+		return 0;
+
+	hcd = bus_to_hcd(udev->bus);
+	if (!hcd || !hcd->driver->disable_usb3_lpm_timeout)
+		return 0;
+
+	udev->lpm_disable_count++;
+	if ((udev->u1_params.timeout == 0 && udev->u1_params.timeout == 0))
+		return 0;
+
+	/* If LPM is enabled, attempt to disable it. */
+	if (usb_disable_link_state(hcd, udev, USB3_LPM_U1))
+		goto enable_lpm;
+	if (usb_disable_link_state(hcd, udev, USB3_LPM_U2))
+		goto enable_lpm;
+
+	return 0;
+
+enable_lpm:
+	usb_enable_lpm(udev);
+	return -EBUSY;
+}
+EXPORT_SYMBOL_GPL(usb_disable_lpm);
+
+/* Grab the bandwidth_mutex before calling usb_disable_lpm() */
+int usb_unlocked_disable_lpm(struct usb_device *udev)
+{
+	struct usb_hcd *hcd = bus_to_hcd(udev->bus);
+	int ret;
+
+	if (!hcd)
+		return -EINVAL;
+
+	mutex_lock(hcd->bandwidth_mutex);
+	ret = usb_disable_lpm(udev);
+	mutex_unlock(hcd->bandwidth_mutex);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(usb_unlocked_disable_lpm);
+
+/*
+ * Attempt to enable device-initiated and hub-initiated U1 and U2 entry.  The
+ * xHCI host policy may prevent U1 or U2 from being enabled.
+ *
+ * Other callers may have disabled link PM, so U1 and U2 entry will be disabled
+ * until the lpm_disable_count drops to zero.  Caller must own the
+ * bandwidth_mutex.
+ */
+void usb_enable_lpm(struct usb_device *udev)
+{
+	struct usb_hcd *hcd;
+
+	if (!udev || !udev->parent ||
+			udev->speed != USB_SPEED_SUPER ||
+			!udev->lpm_capable)
+		return;
+
+	udev->lpm_disable_count--;
+	hcd = bus_to_hcd(udev->bus);
+	/* Double check that we can both enable and disable LPM.
+	 * Device must be configured to accept set feature U1/U2 timeout.
+	 */
+	if (!hcd || !hcd->driver->enable_usb3_lpm_timeout ||
+			!hcd->driver->disable_usb3_lpm_timeout)
+		return;
+
+	if (udev->lpm_disable_count > 0)
+		return;
+
+	usb_enable_link_state(hcd, udev, USB3_LPM_U1);
+	usb_enable_link_state(hcd, udev, USB3_LPM_U2);
+}
+EXPORT_SYMBOL_GPL(usb_enable_lpm);
+
+/* Grab the bandwidth_mutex before calling usb_enable_lpm() */
+void usb_unlocked_enable_lpm(struct usb_device *udev)
+{
+	struct usb_hcd *hcd = bus_to_hcd(udev->bus);
+
+	if (!hcd)
+		return;
+
+	mutex_lock(hcd->bandwidth_mutex);
+	usb_enable_lpm(udev);
+	mutex_unlock(hcd->bandwidth_mutex);
+}
+EXPORT_SYMBOL_GPL(usb_unlocked_enable_lpm);
+
+
 #else	/* CONFIG_PM */
 
 #define hub_suspend		NULL
 #define hub_resume		NULL
 #define hub_reset_resume	NULL
+
+int usb_disable_lpm(struct usb_device *udev)
+{
+	return 0;
+}
+
+void usb_enable_lpm(struct usb_device *udev) { }
+
+int usb_unlocked_disable_lpm(struct usb_device *udev)
+{
+	return 0;
+}
+
+void usb_unlocked_enable_lpm(struct usb_device *udev) { }
 #endif
 
 
···
 	if (udev->wusb == 0 && le16_to_cpu(udev->descriptor.bcdUSB) >= 0x0201) {
 		retval = usb_get_bos_descriptor(udev);
 		if (!retval) {
-			if (udev->bos->ext_cap && (USB_LPM_SUPPORT &
-				le32_to_cpu(udev->bos->ext_cap->bmAttributes)))
-					udev->lpm_capable = 1;
+			udev->lpm_capable = usb_device_supports_lpm(udev);
+			usb_set_lpm_parameters(udev);
 		}
 	}
 
···
 		goto done;
 
 	mutex_lock(hcd->bandwidth_mutex);
+	/* Disable LPM while we reset the device and reinstall the alt settings.
+	 * Device-initiated LPM settings, and system exit latency settings are
+	 * cleared when the device is reset, so we have to set them up again.
+	 */
+	ret = usb_disable_lpm(udev);
+	if (ret) {
+		dev_err(&udev->dev, "%s Failed to disable LPM\n.", __func__);
+		mutex_unlock(hcd->bandwidth_mutex);
+		goto done;
+	}
 	ret = usb_hcd_alloc_bandwidth(udev, udev->actconfig, NULL, NULL);
 	if (ret < 0) {
 		dev_warn(&udev->dev,
 				"Busted HC?  Not enough HCD resources for "
 				"old configuration.\n");
+		usb_enable_lpm(udev);
 		mutex_unlock(hcd->bandwidth_mutex);
 		goto re_enumerate;
 	}
···
 		dev_err(&udev->dev,
 			"can't restore configuration #%d (error=%d)\n",
 			udev->actconfig->desc.bConfigurationValue, ret);
+		usb_enable_lpm(udev);
 		mutex_unlock(hcd->bandwidth_mutex);
 		goto re_enumerate;
   	}
···
 				desc->bInterfaceNumber,
 				desc->bAlternateSetting,
 				ret);
+			usb_unlocked_enable_lpm(udev);
 			goto re_enumerate;
 		}
 	}
 
+	/* Now that the alt settings are re-installed, enable LPM. */
+	usb_unlocked_enable_lpm(udev);
 done:
 	return 0;
  

drivers/usb/core/message.c

···
 	 * Remove the current alt setting and add the new alt setting.
 	 */
 	mutex_lock(hcd->bandwidth_mutex);
+	/* Disable LPM, and re-enable it once the new alt setting is installed,
+	 * so that the xHCI driver can recalculate the U1/U2 timeouts.
+	 */
+	if (usb_disable_lpm(dev)) {
+		dev_err(&iface->dev, "%s Failed to disable LPM\n.", __func__);
+		mutex_unlock(hcd->bandwidth_mutex);
+		return -ENOMEM;
+	}
 	ret = usb_hcd_alloc_bandwidth(dev, NULL, iface->cur_altsetting, alt);
 	if (ret < 0) {
 		dev_info(&dev->dev, "Not enough bandwidth for altsetting %d\n",
 				alternate);
+		usb_enable_lpm(dev);
 		mutex_unlock(hcd->bandwidth_mutex);
 		return ret;
 	}
···
 	} else if (ret < 0) {
 		/* Re-instate the old alt setting */
 		usb_hcd_alloc_bandwidth(dev, NULL, alt, iface->cur_altsetting);
+		usb_enable_lpm(dev);
 		mutex_unlock(hcd->bandwidth_mutex);
 		return ret;
 	}
···
 	usb_disable_interface(dev, iface, true);
 
 	iface->cur_altsetting = alt;
+
+	/* Now that the interface is installed, re-enable LPM. */
+	usb_unlocked_enable_lpm(dev);
 
 	/* If the interface only has one altsetting and the device didn't
 	 * accept the request, we attempt to carry out the equivalent action
···
 	config = dev->actconfig;
 	retval = 0;
 	mutex_lock(hcd->bandwidth_mutex);
+	/* Disable LPM, and re-enable it once the configuration is reset, so
+	 * that the xHCI driver can recalculate the U1/U2 timeouts.
+	 */
+	if (usb_disable_lpm(dev)) {
+		dev_err(&dev->dev, "%s Failed to disable LPM\n.", __func__);
+		mutex_unlock(hcd->bandwidth_mutex);
+		return -ENOMEM;
+	}
 	/* Make sure we have enough bandwidth for each alternate setting 0 */
 	for (i = 0; i < config->desc.bNumInterfaces; i++) {
 		struct usb_interface *intf = config->interface[i];
···
 				usb_hcd_alloc_bandwidth(dev, NULL,
 						alt, intf->cur_altsetting);
 		}
+		usb_enable_lpm(dev);
 		mutex_unlock(hcd->bandwidth_mutex);
 		return retval;
 	}
···
 			create_intf_ep_devs(intf);
 		}
 	}
+	/* Now that the interfaces are installed, re-enable LPM. */
+	usb_unlocked_enable_lpm(dev);
 	return 0;
 }
 EXPORT_SYMBOL_GPL(usb_reset_configuration);
···
 	 * this call fails, the device state is unchanged.
 	 */
 	mutex_lock(hcd->bandwidth_mutex);
+	/* Disable LPM, and re-enable it once the new configuration is
+	 * installed, so that the xHCI driver can recalculate the U1/U2
+	 * timeouts.
+	 */
+	if (usb_disable_lpm(dev)) {
+		dev_err(&dev->dev, "%s Failed to disable LPM\n.", __func__);
+		mutex_unlock(hcd->bandwidth_mutex);
+		return -ENOMEM;
+	}
 	ret = usb_hcd_alloc_bandwidth(dev, cp, NULL, NULL);
 	if (ret < 0) {
+		usb_enable_lpm(dev);
 		mutex_unlock(hcd->bandwidth_mutex);
 		usb_autosuspend_device(dev);
 		goto free_interfaces;
···
 	if (!cp) {
 		usb_set_device_state(dev, USB_STATE_ADDRESS);
 		usb_hcd_alloc_bandwidth(dev, NULL, NULL, NULL);
+		usb_enable_lpm(dev);
 		mutex_unlock(hcd->bandwidth_mutex);
 		usb_autosuspend_device(dev);
 		goto free_interfaces;
···
 	if (cp->string == NULL &&
 			!(dev->quirks & USB_QUIRK_CONFIG_INTF_STRINGS))
 		cp->string = usb_cache_string(dev, cp->desc.iConfiguration);
+
+	/* Now that the interfaces are installed, re-enable LPM. */
+	usb_unlocked_enable_lpm(dev);
 
 	/* Now that all the interfaces are set up, register them
 	 * to trigger binding of drivers to interfaces.  probe()

drivers/usb/host/xhci-hub.c

···
 	struct xhci_bus_state *bus_state;
 	u16 link_state = 0;
 	u16 wake_mask = 0;
+	u16 timeout = 0;
 
 	max_ports = xhci_get_ports(hcd, &port_array);
 	bus_state = &xhci->bus_state[hcd_index(hcd)];
···
 			link_state = (wIndex & 0xff00) >> 3;
 		if (wValue == USB_PORT_FEAT_REMOTE_WAKE_MASK)
 			wake_mask = wIndex & 0xff00;
+		/* The MSB of wIndex is the U1/U2 timeout */
+		timeout = (wIndex & 0xff00) >> 8;
 		wIndex &= 0xff;
 		if (!wIndex || wIndex > max_ports)
 			goto error;
···
 			xhci_writel(xhci, temp, port_array[wIndex]);
 
 			temp = xhci_readl(xhci, port_array[wIndex]);
+			break;
+		case USB_PORT_FEAT_U1_TIMEOUT:
+			if (hcd->speed != HCD_USB3)
+				goto error;
+			temp = xhci_readl(xhci, port_array[wIndex] + 1);
+			temp &= ~PORT_U1_TIMEOUT_MASK;
+			temp |= PORT_U1_TIMEOUT(timeout);
+			xhci_writel(xhci, temp, port_array[wIndex] + 1);
+			break;
+		case USB_PORT_FEAT_U2_TIMEOUT:
+			if (hcd->speed != HCD_USB3)
+				goto error;
+			temp = xhci_readl(xhci, port_array[wIndex] + 1);
+			temp &= ~PORT_U2_TIMEOUT_MASK;
+			temp |= PORT_U2_TIMEOUT(timeout);
+			xhci_writel(xhci, temp, port_array[wIndex] + 1);
 			break;
 		default:
 			goto error;

drivers/usb/host/xhci-mem.c

···
 {
 	struct pci_dev	*pdev = to_pci_dev(xhci_to_hcd(xhci)->self.controller);
 	struct dev_info	*dev_info, *next;
+	struct list_head *tt_list_head;
+	struct list_head *tt;
+	struct list_head *endpoints;
+	struct list_head *ep, *q;
+	struct xhci_tt_bw_info *tt_info;
+	struct xhci_interval_bw_table *bwt;
+	struct xhci_virt_ep *virt_ep;
+
 	unsigned long	flags;
 	int size;
 	int i;
···
 	xhci->event_ring = NULL;
 	xhci_dbg(xhci, "Freed event ring\n");
 
+	if (xhci->lpm_command)
+		xhci_free_command(xhci, xhci->lpm_command);
+	xhci->cmd_ring_reserved_trbs = 0;
 	if (xhci->cmd_ring)
 		xhci_ring_free(xhci, xhci->cmd_ring);
 	xhci->cmd_ring = NULL;
···
 	}
 	spin_unlock_irqrestore(&xhci->lock, flags);
 
+	bwt = &xhci->rh_bw->bw_table;
+	for (i = 0; i < XHCI_MAX_INTERVAL; i++) {
+		endpoints = &bwt->interval_bw[i].endpoints;
+		list_for_each_safe(ep, q, endpoints) {
+			virt_ep = list_entry(ep, struct xhci_virt_ep, bw_endpoint_list);
+			list_del(&virt_ep->bw_endpoint_list);
+			kfree(virt_ep);
+		}
+	}
+
+	tt_list_head = &xhci->rh_bw->tts;
+	list_for_each_safe(tt, q, tt_list_head) {
+		tt_info = list_entry(tt, struct xhci_tt_bw_info, tt_list);
+		list_del(tt);
+		kfree(tt_info);
+	}
+
 	xhci->num_usb2_ports = 0;
 	xhci->num_usb3_ports = 0;
+	xhci->num_active_eps = 0;
 	kfree(xhci->usb2_ports);
 	kfree(xhci->usb3_ports);
 	kfree(xhci->port_array);
···
 	xhci_dbg(xhci, "// Setting command ring address to 0x%x\n", val);
 	xhci_write_64(xhci, val_64, &xhci->op_regs->cmd_ring);
 	xhci_dbg_cmd_ptrs(xhci);
+
+	xhci->lpm_command = xhci_alloc_command(xhci, true, true, flags);
+	if (!xhci->lpm_command)
+		goto fail;
+
+	/* Reserve one command ring TRB for disabling LPM.
+	 * Since the USB core grabs the shared usb_bus bandwidth mutex before
+	 * disabling LPM, we only need to reserve one TRB for all devices.
+	 */
+	xhci->cmd_ring_reserved_trbs++;
 
 	val = xhci_readl(xhci, &xhci->cap_regs->db_off);
 	val &= DBOFF_MASK;

drivers/usb/host/xhci-pci.c

···
 		xhci_dbg(xhci, "QUIRK: Fresco Logic revision %u "
 				"has broken MSI implementation\n",
 				pdev->revision);
+		xhci->quirks |= XHCI_TRUST_TX_LENGTH;
 	}
 
 	if (pdev->vendor == PCI_VENDOR_ID_NEC)
···
 	/* AMD PLL quirk */
 	if (pdev->vendor == PCI_VENDOR_ID_AMD && usb_amd_find_chipset_info())
 		xhci->quirks |= XHCI_AMD_PLL_FIX;
+	if (pdev->vendor == PCI_VENDOR_ID_INTEL) {
+		xhci->quirks |= XHCI_LPM_SUPPORT;
+		xhci->quirks |= XHCI_INTEL_HOST;
+	}
 	if (pdev->vendor == PCI_VENDOR_ID_INTEL &&
 			pdev->device == PCI_DEVICE_ID_INTEL_PANTHERPOINT_XHCI) {
 		xhci->quirks |= XHCI_SPURIOUS_SUCCESS;
···
 	if (retval)
 		goto put_usb3_hcd;
 	/* Roothub already marked as USB 3.0 speed */
+
+	/* We know the LPM timeout algorithms for this host, let the USB core
+	 * enable and disable LPM for devices under the USB 3.0 roothub.
+	 */
+	if (xhci->quirks & XHCI_LPM_SUPPORT)
+		hcd_to_bus(xhci->shared_hcd)->root_hub->lpm_capable = 1;
+
 	return 0;
 
 put_usb3_hcd:
···
 	 */
 	.update_device =        xhci_update_device,
 	.set_usb2_hw_lpm =	xhci_set_usb2_hardware_lpm,
+	.enable_usb3_lpm_timeout =	xhci_enable_usb3_lpm_timeout,
+	.disable_usb3_lpm_timeout =	xhci_disable_usb3_lpm_timeout,
 };
 
 /*-------------------------------------------------------------------------*/

drivers/usb/host/xhci-ring.c

···
 	/* handle completion code */
 	switch (trb_comp_code) {
 	case COMP_SUCCESS:
-		frame->status = 0;
-		break;
+		if (TRB_LEN(le32_to_cpu(event->transfer_len)) == 0) {
+			frame->status = 0;
+			break;
+		}
+		if ((xhci->quirks & XHCI_TRUST_TX_LENGTH))
+			trb_comp_code = COMP_SHORT_TX;
 	case COMP_SHORT_TX:
 		frame->status = td->urb->transfer_flags & URB_SHORT_NOT_OK ?
 				-EREMOTEIO : 0;
···
 	switch (trb_comp_code) {
 	case COMP_SUCCESS:
 		/* Double check that the HW transferred everything. */
-		if (event_trb != td->last_trb) {
+		if (event_trb != td->last_trb ||
+				TRB_LEN(le32_to_cpu(event->transfer_len)) != 0) {
 			xhci_warn(xhci, "WARN Successful completion "
 					"on short TX\n");
 			if (td->urb->transfer_flags & URB_SHORT_NOT_OK)
 				*status = -EREMOTEIO;
 			else
 				*status = 0;
+			if ((xhci->quirks & XHCI_TRUST_TX_LENGTH))
+				trb_comp_code = COMP_SHORT_TX;
 		} else {
 			*status = 0;
 		}
···
 	 * transfer type
 	 */
 	case COMP_SUCCESS:
+		if (TRB_LEN(le32_to_cpu(event->transfer_len)) == 0)
+			break;
+		if (xhci->quirks & XHCI_TRUST_TX_LENGTH)
+			trb_comp_code = COMP_SHORT_TX;
+		else
+			xhci_warn(xhci, "WARN Successful completion on short TX: "
+					"needs XHCI_TRUST_TX_LENGTH quirk?\n");
 	case COMP_SHORT_TX:
 		break;
 	case COMP_STOP:
···
 
 /* Queue an evaluate context command TRB */
 int xhci_queue_evaluate_context(struct xhci_hcd *xhci, dma_addr_t in_ctx_ptr,
-		u32 slot_id)
+		u32 slot_id, bool command_must_succeed)
 {
 	return queue_command(xhci, lower_32_bits(in_ctx_ptr),
 			upper_32_bits(in_ctx_ptr), 0,
 			TRB_TYPE(TRB_EVAL_CONTEXT) | SLOT_ID_FOR_TRB(slot_id),
-			false);
+			command_must_succeed);
 }
 
 /*

drivers/usb/host/xhci.c

···
 				udev->slot_id, must_succeed);
 	else
 		ret = xhci_queue_evaluate_context(xhci, in_ctx->dma,
-				udev->slot_id);
+				udev->slot_id, must_succeed);
 	if (ret < 0) {
 		if (command)
 			list_del(&command->cmd_list);
···
 	spin_unlock_irqrestore(&xhci->lock, flags);
 	return 0;
 }
+
+/*---------------------- USB 3.0 Link PM functions ------------------------*/
+
+/* Service interval in nanoseconds = 2^(bInterval - 1) * 125us * 1000ns / 1us */
+static unsigned long long xhci_service_interval_to_ns(
+		struct usb_endpoint_descriptor *desc)
+{
+	return (1 << (desc->bInterval - 1)) * 125 * 1000;
+}
+
+static u16 xhci_get_timeout_no_hub_lpm(struct usb_device *udev,
+		enum usb3_link_state state)
+{
+	unsigned long long sel;
+	unsigned long long pel;
+	unsigned int max_sel_pel;
+	char *state_name;
+
+	switch (state) {
+	case USB3_LPM_U1:
+		/* Convert SEL and PEL stored in nanoseconds to microseconds */
+		sel = DIV_ROUND_UP(udev->u1_params.sel, 1000);
+		pel = DIV_ROUND_UP(udev->u1_params.pel, 1000);
+		max_sel_pel = USB3_LPM_MAX_U1_SEL_PEL;
+		state_name = "U1";
+		break;
+	case USB3_LPM_U2:
+		sel = DIV_ROUND_UP(udev->u2_params.sel, 1000);
+		pel = DIV_ROUND_UP(udev->u2_params.pel, 1000);
+		max_sel_pel = USB3_LPM_MAX_U2_SEL_PEL;
+		state_name = "U2";
+		break;
+	default:
+		dev_warn(&udev->dev, "%s: Can't get timeout for non-U1 or U2 state.\n",
+				__func__);
+		return -EINVAL;
+	}
+
+	if (sel <= max_sel_pel && pel <= max_sel_pel)
+		return USB3_LPM_DEVICE_INITIATED;
+
+	if (sel > max_sel_pel)
+		dev_dbg(&udev->dev, "Device-initiated %s disabled "
+				"due to long SEL %llu ms\n",
+				state_name, sel);
+	else
+		dev_dbg(&udev->dev, "Device-initiated %s disabled "
+				"due to long PEL %llu\n ms",
+				state_name, pel);
+	return USB3_LPM_DISABLED;
+}
+
+/* Returns the hub-encoded U1 timeout value.
+ * The U1 timeout should be the maximum of the following values:
+ *  - For control endpoints, U1 system exit latency (SEL) * 3
+ *  - For bulk endpoints, U1 SEL * 5
+ *  - For interrupt endpoints:
+ *    - Notification EPs, U1 SEL * 3
+ *    - Periodic EPs, max(105% of bInterval, U1 SEL * 2)
+ *  - For isochronous endpoints, max(105% of bInterval, U1 SEL * 2)
+ */
+static u16 xhci_calculate_intel_u1_timeout(struct usb_device *udev,
+		struct usb_endpoint_descriptor *desc)
+{
+	unsigned long long timeout_ns;
+	int ep_type;
+	int intr_type;
+
+	ep_type = usb_endpoint_type(desc);
+	switch (ep_type) {
+	case USB_ENDPOINT_XFER_CONTROL:
+		timeout_ns = udev->u1_params.sel * 3;
+		break;
+	case USB_ENDPOINT_XFER_BULK:
+		timeout_ns = udev->u1_params.sel * 5;
+		break;
+	case USB_ENDPOINT_XFER_INT:
+		intr_type = usb_endpoint_interrupt_type(desc);
+		if (intr_type == USB_ENDPOINT_INTR_NOTIFICATION) {
+			timeout_ns = udev->u1_params.sel * 3;
+			break;
+		}
+		/* Otherwise the calculation is the same as isoc eps */
+	case USB_ENDPOINT_XFER_ISOC:
+		timeout_ns = xhci_service_interval_to_ns(desc);
+		timeout_ns = DIV_ROUND_UP(timeout_ns * 105, 100);
+		if (timeout_ns < udev->u1_params.sel * 2)
+			timeout_ns = udev->u1_params.sel * 2;
+		break;
+	default:
+		return 0;
+	}
+
+	/* The U1 timeout is encoded in 1us intervals. */
+	timeout_ns = DIV_ROUND_UP(timeout_ns, 1000);
+	/* Don't return a timeout of zero, because that's USB3_LPM_DISABLED. */
+	if (timeout_ns == USB3_LPM_DISABLED)
+		timeout_ns++;
+
+	/* If the necessary timeout value is bigger than what we can set in the
+	 * USB 3.0 hub, we have to disable hub-initiated U1.
+	 */
+	if (timeout_ns <= USB3_LPM_U1_MAX_TIMEOUT)
+		return timeout_ns;
+	dev_dbg(&udev->dev, "Hub-initiated U1 disabled "
+			"due to long timeout %llu ms\n", timeout_ns);
+	return xhci_get_timeout_no_hub_lpm(udev, USB3_LPM_U1);
+}
+
+/* Returns the hub-encoded U2 timeout value.
+ * The U2 timeout should be the maximum of:
+ *  - 10 ms (to avoid the bandwidth impact on the scheduler)
+ *  - largest bInterval of any active periodic endpoint (to avoid going
+ *    into lower power link states between intervals).
+ *  - the U2 Exit Latency of the device
+ */
+static u16 xhci_calculate_intel_u2_timeout(struct usb_device *udev,
+		struct usb_endpoint_descriptor *desc)
+{
+	unsigned long long timeout_ns;
+	unsigned long long u2_del_ns;
+
+	timeout_ns = 10 * 1000 * 1000;
+
+	if ((usb_endpoint_xfer_int(desc) || usb_endpoint_xfer_isoc(desc)) &&
+			(xhci_service_interval_to_ns(desc) > timeout_ns))
+		timeout_ns = xhci_service_interval_to_ns(desc);
+
+	u2_del_ns = udev->bos->ss_cap->bU2DevExitLat * 1000;
+	if (u2_del_ns > timeout_ns)
+		timeout_ns = u2_del_ns;
+
+	/* The U2 timeout is encoded in 256us intervals */
+	timeout_ns = DIV_ROUND_UP(timeout_ns, 256 * 1000);
+	/* If the necessary timeout value is bigger than what we can set in the
+	 * USB 3.0 hub, we have to disable hub-initiated U2.
+	 */
+	if (timeout_ns <= USB3_LPM_U2_MAX_TIMEOUT)
+		return timeout_ns;
+	dev_dbg(&udev->dev, "Hub-initiated U2 disabled "
+			"due to long timeout %llu ms\n", timeout_ns);
+	return xhci_get_timeout_no_hub_lpm(udev, USB3_LPM_U2);
+}
+
+static u16 xhci_call_host_update_timeout_for_endpoint(struct xhci_hcd *xhci,
+		struct usb_device *udev,
+		struct usb_endpoint_descriptor *desc,
+		enum usb3_link_state state,
+		u16 *timeout)
+{
+	if (state == USB3_LPM_U1) {
+		if (xhci->quirks & XHCI_INTEL_HOST)
+			return xhci_calculate_intel_u1_timeout(udev, desc);
+	} else {
+		if (xhci->quirks & XHCI_INTEL_HOST)
+			return xhci_calculate_intel_u2_timeout(udev, desc);
+	}
+
+	return USB3_LPM_DISABLED;
+}
+
+static int xhci_update_timeout_for_endpoint(struct xhci_hcd *xhci,
+		struct usb_device *udev,
+		struct usb_endpoint_descriptor *desc,
+		enum usb3_link_state state,
+		u16 *timeout)
+{
+	u16 alt_timeout;
+
+	alt_timeout = xhci_call_host_update_timeout_for_endpoint(xhci, udev,
+		desc, state, timeout);
+
+	/* If we found we can't enable hub-initiated LPM, or
+	 * the U1 or U2 exit latency was too high to allow
+	 * device-initiated LPM as well, just stop searching.
+	 */
+	if (alt_timeout == USB3_LPM_DISABLED ||
+			alt_timeout == USB3_LPM_DEVICE_INITIATED) {
+		*timeout = alt_timeout;
+		return -E2BIG;
+	}
+	if (alt_timeout > *timeout)
+		*timeout = alt_timeout;
+	return 0;
+}
+
+static int xhci_update_timeout_for_interface(struct xhci_hcd *xhci,
+		struct usb_device *udev,
+		struct usb_host_interface *alt,
+		enum usb3_link_state state,
+		u16 *timeout)
+{
+	int j;
+
+	for (j = 0; j < alt->desc.bNumEndpoints; j++) {
+		if (xhci_update_timeout_for_endpoint(xhci, udev,
+					&alt->endpoint[j].desc, state, timeout))
+			return -E2BIG;
+		continue;
+	}
+	return 0;
+}
+
+static int xhci_check_intel_tier_policy(struct usb_device *udev,
+		enum usb3_link_state state)
+{
+	struct usb_device *parent;
+	unsigned int num_hubs;
+
+	if (state == USB3_LPM_U2)
+		return 0;
+
+	/* Don't enable U1 if the device is on a 2nd tier hub or lower. */
+	for (parent = udev->parent, num_hubs = 0; parent->parent;
+			parent = parent->parent)
+		num_hubs++;
+
+	if (num_hubs < 2)
+		return 0;
+
+	dev_dbg(&udev->dev, "Disabling U1 link state for device"
+			" below second-tier hub.\n");
+	dev_dbg(&udev->dev, "Plug device into first-tier hub "
+			"to decrease power consumption.\n");
+	return -E2BIG;
+}
+
+static int xhci_check_tier_policy(struct xhci_hcd *xhci,
+		struct usb_device *udev,
+		enum usb3_link_state state)
+{
+	if (xhci->quirks & XHCI_INTEL_HOST)
+		return xhci_check_intel_tier_policy(udev, state);
+	return -EINVAL;
+}
+
+/* Returns the U1 or U2 timeout that should be enabled.
+ * If the tier check or timeout setting functions return with a non-zero exit
+ * code, that means the timeout value has been finalized and we shouldn't look
+ * at any more endpoints.
+ */
+static u16 xhci_calculate_lpm_timeout(struct usb_hcd *hcd,
+			struct usb_device *udev, enum usb3_link_state state)
+{
+	struct xhci_hcd *xhci = hcd_to_xhci(hcd);
+	struct usb_host_config *config;
+	char *state_name;
+	int i;
+	u16 timeout = USB3_LPM_DISABLED;
+
+	if (state == USB3_LPM_U1)
+		state_name = "U1";
+	else if (state == USB3_LPM_U2)
+		state_name = "U2";
+	else {
+		dev_warn(&udev->dev, "Can't enable unknown link state %i\n",
+				state);
+		return timeout;
+	}
+
+	if (xhci_check_tier_policy(xhci, udev, state) < 0)
+		return timeout;
+
+	/* Gather some information about the currently installed configuration
+	 * and alternate interface settings.
+	 */
+	if (xhci_update_timeout_for_endpoint(xhci, udev, &udev->ep0.desc,
+			state, &timeout))
+		return timeout;
+
+	config = udev->actconfig;
+	if (!config)
+		return timeout;
+
+	for (i = 0; i < USB_MAXINTERFACES; i++) {
+		struct usb_driver *driver;
+		struct usb_interface *intf = config->interface[i];
+
+		if (!intf)
+			continue;
+
+		/* Check if any currently bound drivers want hub-initiated LPM
+		 * disabled.
+		 */
+		if (intf->dev.driver) {
+			driver = to_usb_driver(intf->dev.driver);
+			if (driver && driver->disable_hub_initiated_lpm) {
+				dev_dbg(&udev->dev, "Hub-initiated %s disabled "
+						"at request of driver %s\n",
+						state_name, driver->name);
+				return xhci_get_timeout_no_hub_lpm(udev, state);
+			}
+		}
+
+		/* Not sure how this could happen... */
+		if (!intf->cur_altsetting)
+			continue;
+
+		if (xhci_update_timeout_for_interface(xhci, udev,
+					intf->cur_altsetting,
+					state, &timeout))
+			return timeout;
+	}
+	return timeout;
+}
+
+/*
+ * Issue an Evaluate Context command to change the Maximum Exit Latency in the
+ * slot context.  If that succeeds, store the new MEL in the xhci_virt_device.
+ */
+static int xhci_change_max_exit_latency(struct xhci_hcd *xhci,
+			struct usb_device *udev, u16 max_exit_latency)
+{
+	struct xhci_virt_device *virt_dev;
+	struct xhci_command *command;
+	struct xhci_input_control_ctx *ctrl_ctx;
+	struct xhci_slot_ctx *slot_ctx;
+	unsigned long flags;
+	int ret;
+
+	spin_lock_irqsave(&xhci->lock, flags);
+	if (max_exit_latency == xhci->devs[udev->slot_id]->current_mel) {
+		spin_unlock_irqrestore(&xhci->lock, flags);
+		return 0;
+	}
+
+	/* Attempt to issue an Evaluate Context command to change the MEL. */
+	virt_dev = xhci->devs[udev->slot_id];
+	command = xhci->lpm_command;
+	xhci_slot_copy(xhci, command->in_ctx, virt_dev->out_ctx);
+	spin_unlock_irqrestore(&xhci->lock, flags);
+
+	ctrl_ctx = xhci_get_input_control_ctx(xhci, command->in_ctx);
+	ctrl_ctx->add_flags |= cpu_to_le32(SLOT_FLAG);
+	slot_ctx = xhci_get_slot_ctx(xhci, command->in_ctx);
+	slot_ctx->dev_info2 &= cpu_to_le32(~((u32) MAX_EXIT));
+	slot_ctx->dev_info2 |= cpu_to_le32(max_exit_latency);
+
+	xhci_dbg(xhci, "Set up evaluate context for LPM MEL change.\n");
+	xhci_dbg(xhci, "Slot %u Input Context:\n", udev->slot_id);
+	xhci_dbg_ctx(xhci, command->in_ctx, 0);
+
+	/* Issue and wait for the evaluate context command. */
+	ret = xhci_configure_endpoint(xhci, udev, command,
+			true, true);
+	xhci_dbg(xhci, "Slot %u Output Context:\n", udev->slot_id);
+	xhci_dbg_ctx(xhci, virt_dev->out_ctx, 0);
+
+	if (!ret) {
+		spin_lock_irqsave(&xhci->lock, flags);
+		virt_dev->current_mel = max_exit_latency;
+		spin_unlock_irqrestore(&xhci->lock, flags);
+	}
+	return ret;
+}
+
+static int calculate_max_exit_latency(struct usb_device *udev,
+		enum usb3_link_state state_changed,
+		u16 hub_encoded_timeout)
+{
+	unsigned long long u1_mel_us = 0;
+	unsigned long long u2_mel_us = 0;
+	unsigned long long mel_us = 0;
+	bool disabling_u1;
+	bool disabling_u2;
+	bool enabling_u1;
+	bool enabling_u2;
+
+	disabling_u1 = (state_changed == USB3_LPM_U1 &&
+			hub_encoded_timeout == USB3_LPM_DISABLED);
+	disabling_u2 = (state_changed == USB3_LPM_U2 &&
+			hub_encoded_timeout == USB3_LPM_DISABLED);
+
+	enabling_u1 = (state_changed == USB3_LPM_U1 &&
+			hub_encoded_timeout != USB3_LPM_DISABLED);
+	enabling_u2 = (state_changed == USB3_LPM_U2 &&
+			hub_encoded_timeout != USB3_LPM_DISABLED);
+
+	/* If U1 was already enabled and we're not disabling it,
+	 * or we're going to enable U1, account for the U1 max exit latency.
+	 */
+	if ((udev->u1_params.timeout != USB3_LPM_DISABLED && !disabling_u1) ||
+			enabling_u1)
+		u1_mel_us = DIV_ROUND_UP(udev->u1_params.mel, 1000);
+	if ((udev->u2_params.timeout != USB3_LPM_DISABLED && !disabling_u2) ||
+			enabling_u2)
+		u2_mel_us = DIV_ROUND_UP(udev->u2_params.mel, 1000);
+
+	if (u1_mel_us > u2_mel_us)
+		mel_us = u1_mel_us;
+	else
+		mel_us = u2_mel_us;
+	/* xHCI host controller max exit latency field is only 16 bits wide. */
+	if (mel_us > MAX_EXIT) {
+		dev_warn(&udev->dev, "Link PM max exit latency of %lluus "
+				"is too big.\n", mel_us);
+		return -E2BIG;
+	}
+	return mel_us;
+}
+
+/* Returns the USB3 hub-encoded value for the U1/U2 timeout. */
+int xhci_enable_usb3_lpm_timeout(struct usb_hcd *hcd,
+			struct usb_device *udev, enum usb3_link_state state)
+{
+	struct xhci_hcd	*xhci;
+	u16 hub_encoded_timeout;
+	int mel;
+	int ret;
+
+	xhci = hcd_to_xhci(hcd);
+	/* The LPM timeout values are pretty host-controller specific, so don't
+	 * enable hub-initiated timeouts unless the vendor has provided
+	 * information about their timeout algorithm.
+	 */
+	if (!xhci || !(xhci->quirks & XHCI_LPM_SUPPORT) ||
+			!xhci->devs[udev->slot_id])
+		return USB3_LPM_DISABLED;
+
+	hub_encoded_timeout = xhci_calculate_lpm_timeout(hcd, udev, state);
+	mel = calculate_max_exit_latency(udev, state, hub_encoded_timeout);
+	if (mel < 0) {
+		/* Max Exit Latency is too big, disable LPM. */
+		hub_encoded_timeout = USB3_LPM_DISABLED;
+		mel = 0;
+	}
+
+	ret = xhci_change_max_exit_latency(xhci, udev, mel);
+	if (ret)
+		return ret;
+	return hub_encoded_timeout;
+}
+
+int xhci_disable_usb3_lpm_timeout(struct usb_hcd *hcd,
+			struct usb_device *udev, enum usb3_link_state state)
+{
+	struct xhci_hcd	*xhci;
+	u16 mel;
+	int ret;
+
+	xhci = hcd_to_xhci(hcd);
+	if (!xhci || !(xhci->quirks & XHCI_LPM_SUPPORT) ||
+			!xhci->devs[udev->slot_id])
+		return 0;
+
+	mel = calculate_max_exit_latency(udev, state, USB3_LPM_DISABLED);
+	ret = xhci_change_max_exit_latency(xhci, udev, mel);
+	if (ret)
+		return ret;
+	return 0;
+}
+/*-------------------------------------------------------------------------*/
 
 int xhci_update_device(struct usb_hcd *hcd, struct usb_device *udev)
 {

drivers/usb/host/xhci.h

···
  * Timeout can be up to 127us.  0xFF means an infinite timeout.
  */
 #define PORT_U1_TIMEOUT(p)	((p) & 0xff)
+#define PORT_U1_TIMEOUT_MASK	0xff
 /* Inactivity timer value for transitions into U2 */
 #define PORT_U2_TIMEOUT(p)	(((p) & 0xff) << 8)
+#define PORT_U2_TIMEOUT_MASK	(0xff << 8)
 /* Bits 24:31 for port testing */
 
 /* USB2 Protocol PORTSPMSC */
···
 	u8				real_port;
 	struct xhci_interval_bw_table	*bw_table;
 	struct xhci_tt_bw_info		*tt_info;
+	/* The current max exit latency for the enabled USB3 link states. */
+	u16				current_mel;
 };
 
 /*
···
 	/* slot enabling and address device helpers */
 	struct completion	addr_dev;
 	int slot_id;
+	/* For USB 3.0 LPM enable/disable. */
+	struct xhci_command		*lpm_command;
 	/* Internal mirror of the HW's dcbaa */
 	struct xhci_virt_device	*devs[MAX_HC_SLOTS];
 	/* For keeping track of bandwidth domains per roothub. */
···
 #define XHCI_RESET_ON_RESUME	(1 << 7)
 #define	XHCI_SW_BW_CHECKING	(1 << 8)
 #define XHCI_AMD_0x96_HOST	(1 << 9)
+#define XHCI_TRUST_TX_LENGTH	(1 << 10)
+#define XHCI_LPM_SUPPORT	(1 << 11)
+#define XHCI_INTEL_HOST		(1 << 12)
 	unsigned int		num_active_eps;
 	unsigned int		limit_active_eps;
 	/* There are two roothubs to keep track of bus suspend info for */
···
 int xhci_queue_configure_endpoint(struct xhci_hcd *xhci, dma_addr_t in_ctx_ptr,
 		u32 slot_id, bool command_must_succeed);
 int xhci_queue_evaluate_context(struct xhci_hcd *xhci, dma_addr_t in_ctx_ptr,
-		u32 slot_id);
+		u32 slot_id, bool command_must_succeed);
 int xhci_queue_reset_ep(struct xhci_hcd *xhci, int slot_id,
 		unsigned int ep_index);
 int xhci_queue_reset_device(struct xhci_hcd *xhci, u32 slot_id);
···
 /* xHCI roothub code */
 void xhci_set_link_state(struct xhci_hcd *xhci, __le32 __iomem **port_array,
 				int port_id, u32 link_state);
+int xhci_enable_usb3_lpm_timeout(struct usb_hcd *hcd,
+			struct usb_device *udev, enum usb3_link_state state);
+int xhci_disable_usb3_lpm_timeout(struct usb_hcd *hcd,
+			struct usb_device *udev, enum usb3_link_state state);
 void xhci_test_and_clear_bit(struct xhci_hcd *xhci, __le32 __iomem **port_array,
 				int port_id, u32 port_bit);
 int xhci_hub_control(struct usb_hcd *hcd, u16 typeReq, u16 wValue, u16 wIndex,

include/linux/usb.h

···
 	USB_DEVICE_FIXED,
 };
 
+/*
+ * USB 3.0 Link Power Management (LPM) parameters.
+ *
+ * PEL and SEL are USB 3.0 Link PM latencies for device-initiated LPM exit.
+ * MEL is the USB 3.0 Link PM latency for host-initiated LPM exit.
+ * All three are stored in nanoseconds.
+ */
+struct usb3_lpm_parameters {
+	/*
+	 * Maximum exit latency (MEL) for the host to send a packet to the
+	 * device (either a Ping for isoc endpoints, or a data packet for
+	 * interrupt endpoints), the hubs to decode the packet, and for all hubs
+	 * in the path to transition the links to U0.
+	 */
+	unsigned int mel;
+	/*
+	 * Maximum exit latency for a device-initiated LPM transition to bring
+	 * all links into U0.  Abbreviated as "PEL" in section 9.4.12 of the USB
+	 * 3.0 spec, with no explanation of what "P" stands for.  "Path"?
+	 */
+	unsigned int pel;
+
+	/*
+	 * The System Exit Latency (SEL) includes PEL, and three other
+	 * latencies.  After a device initiates a U0 transition, it will take
+	 * some time from when the device sends the ERDY to when it will finally
+	 * receive the data packet.  Basically, SEL should be the worse-case
+	 * latency from when a device starts initiating a U0 transition to when
+	 * it will get data.
+	 */
+	unsigned int sel;
+	/*
+	 * The idle timeout value that is currently programmed into the parent
+	 * hub for this device.  When the timer counts to zero, the parent hub
+	 * will initiate an LPM transition to either U1 or U2.
+	 */
+	int timeout;
+};
+
 /**
  * struct usb_device - kernel's representation of a USB device
  * @devnum: device number; address on a USB bus
···
  *	specific data for the device.
  * @slot_id: Slot ID assigned by xHCI
  * @removable: Device can be physically removed from this port
+ * @u1_params: exit latencies for USB3 U1 LPM state, and hub-initiated timeout.
+ * @u2_params: exit latencies for USB3 U2 LPM state, and hub-initiated timeout.
+ * @lpm_disable_count: Ref count used by usb_disable_lpm() and usb_enable_lpm()
+ *	to keep track of the number of functions that require USB 3.0 Link Power
+ *	Management to be disabled for this usb_device.  This count should only
+ *	be manipulated by those functions, with the bandwidth_mutex is held.
  *
  * Notes:
  * Usbcore drivers should not set usbdev->state directly.  Instead use
···
 	unsigned lpm_capable:1;
 	unsigned usb2_hw_lpm_capable:1;
 	unsigned usb2_hw_lpm_enabled:1;
+	unsigned usb3_lpm_enabled:1;
 	int string_langid;
 
 	/* static strings from the device */
···
 	struct wusb_dev *wusb_dev;
 	int slot_id;
 	enum usb_device_removable removable;
+	struct usb3_lpm_parameters u1_params;
+	struct usb3_lpm_parameters u2_params;
+	unsigned lpm_disable_count;
+	unsigned hub_initiated_lpm_disable_count;
 };
 #define	to_usb_device(d) container_of(d, struct usb_device, dev)
 
···
 extern void usb_autopm_put_interface_async(struct usb_interface *intf);
 extern void usb_autopm_get_interface_no_resume(struct usb_interface *intf);
 extern void usb_autopm_put_interface_no_suspend(struct usb_interface *intf);
+
+extern int usb_disable_lpm(struct usb_device *udev);
+extern void usb_enable_lpm(struct usb_device *udev);
+/* Same as above, but these functions lock/unlock the bandwidth_mutex. */
+extern int usb_unlocked_disable_lpm(struct usb_device *udev);
+extern void usb_unlocked_enable_lpm(struct usb_device *udev);
 
 static inline void usb_mark_last_busy(struct usb_device *udev)
 {
···
  *	for interfaces bound to this driver.
  * @soft_unbind: if set to 1, the USB core will not kill URBs and disable
  *	endpoints before calling the driver's disconnect method.
+ * @disable_hub_initiated_lpm: if set to 0, the USB core will not allow hubs
+ *	to initiate lower power link state transitions when an idle timeout
+ *	occurs.  Device-initiated USB 3.0 link PM will still be allowed.
  *
  * USB interface drivers must provide a name, probe() and disconnect()
  * methods, and an id_table.  Other driver fields are optional.
···
 	struct usbdrv_wrap drvwrap;
 	unsigned int no_dynamic_id:1;
 	unsigned int supports_autosuspend:1;
+	unsigned int disable_hub_initiated_lpm:1;
 	unsigned int soft_unbind:1;
 };
 #define	to_usb_driver(d) container_of(d, struct usb_driver, drvwrap.driver)

include/linux/usb/ch11.h

···
 #define USB_PORT_FEAT_C_BH_PORT_RESET		29
 #define USB_PORT_FEAT_FORCE_LINKPM_ACCEPT	30
 
+#define USB_PORT_LPM_TIMEOUT(p)			(((p) & 0xff) << 8)
+
 /* USB 3.0 hub remote wake mask bits, see table 10-14 */
 #define USB_PORT_FEAT_REMOTE_WAKE_CONNECT	(1 << 8)
 #define USB_PORT_FEAT_REMOTE_WAKE_DISCONNECT	(1 << 9)

include/linux/usb/ch9.h

···
 #define USB_ENDPOINT_XFER_INT		3
 #define USB_ENDPOINT_MAX_ADJUSTABLE	0x80
 
+/* The USB 3.0 spec redefines bits 5:4 of bmAttributes as interrupt ep type. */
+#define USB_ENDPOINT_INTRTYPE		0x30
+#define USB_ENDPOINT_INTR_PERIODIC	(0 << 4)
+#define USB_ENDPOINT_INTR_NOTIFICATION	(1 << 4)
+
 #define USB_ENDPOINT_SYNCTYPE		0x0c
 #define USB_ENDPOINT_SYNC_NONE		(0 << 2)
 #define USB_ENDPOINT_SYNC_ASYNC		(1 << 2)
···
 static inline int usb_endpoint_maxp(const struct usb_endpoint_descriptor *epd)
 {
 	return __le16_to_cpu(epd->wMaxPacketSize);
+}
+
+static inline int usb_endpoint_interrupt_type(
+		const struct usb_endpoint_descriptor *epd)
+{
+	return epd->bmAttributes & USB_ENDPOINT_INTRTYPE;
 }
 
 /*-------------------------------------------------------------------------*/
···
 	 * suspend states.  (L2 being original USB 1.1 suspend.)
 	 */
 };
+
+enum usb3_link_state {
+	USB3_LPM_U0 = 0,
+	USB3_LPM_U1,
+	USB3_LPM_U2,
+	USB3_LPM_U3
+};
+
+/*
+ * A U1 timeout of 0x0 means the parent hub will reject any transitions to U1.
+ * 0xff means the parent hub will accept transitions to U1, but will not
+ * initiate a transition.
+ *
+ * A U1 timeout of 0x1 to 0x7F also causes the hub to initiate a transition to
+ * U1 after that many microseconds.  Timeouts of 0x80 to 0xFE are reserved
+ * values.
+ *
+ * A U2 timeout of 0x0 means the parent hub will reject any transitions to U2.
+ * 0xff means the parent hub will accept transitions to U2, but will not
+ * initiate a transition.
+ *
+ * A U2 timeout of 0x1 to 0xFE also causes the hub to initiate a transition to
+ * U2 after N*256 microseconds.  Therefore a U2 timeout value of 0x1 means a U2
+ * idle timer of 256 microseconds, 0x2 means 512 microseconds, 0xFE means
+ * 65.024ms.
+ */
+#define USB3_LPM_DISABLED		0x0
+#define USB3_LPM_U1_MAX_TIMEOUT		0x7F
+#define USB3_LPM_U2_MAX_TIMEOUT		0xFE
+#define USB3_LPM_DEVICE_INITIATED	0xFF
+
+struct usb_set_sel_req {
+	__u8	u1_sel;
+	__u8	u1_pel;
+	__le16	u2_sel;
+	__le16	u2_pel;
+} __attribute__ ((packed));
+
+/*
+ * The Set System Exit Latency control transfer provides one byte each for
+ * U1 SEL and U1 PEL, so the max exit latency is 0xFF.  U2 SEL and U2 PEL each
+ * are two bytes long.
+ */
+#define USB3_LPM_MAX_U1_SEL_PEL		0xFF
+#define USB3_LPM_MAX_U2_SEL_PEL		0xFFFF
 
 /*-------------------------------------------------------------------------*/
 

include/linux/usb/hcd.h

···
 		 */
 	int	(*update_device)(struct usb_hcd *, struct usb_device *);
 	int	(*set_usb2_hw_lpm)(struct usb_hcd *, struct usb_device *, int);
+	/* USB 3.0 Link Power Management */
+		/* Returns the USB3 hub-encoded value for the U1/U2 timeout. */
+	int	(*enable_usb3_lpm_timeout)(struct usb_hcd *,
+			struct usb_device *, enum usb3_link_state state);
+		/* The xHCI host controller can still fail the command to
+		 * disable the LPM timeouts, so this can return an error code.
+		 */
+	int	(*disable_usb3_lpm_timeout)(struct usb_hcd *,
+			struct usb_device *, enum usb3_link_state state);
 };
 
 extern int usb_hcd_link_urb_to_ep(struct usb_hcd *hcd, struct urb *urb);