[RFC PATCH v1 0/3] usbnet: runtime suspend when link becomes down

[RFC PATCH v1 0/3] usbnet: runtime suspend when link becomes down

[Ming Lei]

Hi,

Currently only very few usbnet devices support the traffic based
runtime PM, eg. wake up devices if there are packets to be transmitted.

For the below situation, it should make sense to runtime suspend usbnet
device to save power:

	- after network link becomes down

This patch implements the runtime PM triggered by network link change
event, and it works basically on asix usbnet device after a simple
runtime PM test.

Change Log:
v1:
	-- use system_freezable_wq to fix deadlock by calling
	usbnet_link_updated in same workqueue
	-- use system_freezable_wq to stop link check work during
	system sleep
	-- fix bug of possible change of previous autosuspend_delay
	-- set/clear 'needs_remote_wakeup' for devices which support
	remote wakeup on link change
	-- convert EXPORT_SYMBOL_GPL to EXPORT_SYMBOL
	-- introduce module parameter of link_autocheck_time
	-- introduce link_rpm_supported to not start link
	runtime PM for devices which can't detect link change
	(such as smsc95xx)

	Thanks for Oliver's review.

 drivers/net/usb/asix_devices.c |    6 +-
 drivers/net/usb/cdc_ether.c    |    5 +-
 drivers/net/usb/cdc_ncm.c      |    9 +-
 drivers/net/usb/dm9601.c       |    7 +-
 drivers/net/usb/mcs7830.c      |    6 +-
 drivers/net/usb/sierra_net.c   |    6 +-
 drivers/net/usb/usbnet.c       |  280 +++++++++++++++++++++++++++++++++++++++-
 include/linux/usb/usbnet.h     |   22 +++-
 8 files changed, 306 insertions(+), 35 deletions(-)


Thanks,
--
Ming Lei

--
To unsubscribe from this list: send the line "unsubscribe linux-usb" in
the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

[RFC PATCH v1 1/3] usbnet: introduce usbnet_link_change API

[Ming Lei]

This patch introduces the API of usbnet_link_change, so that
usbnet can trace the link change, which may help to implement
the later runtime PM triggered by usb ethernet link change.

Signed-off-by: Ming Lei <ming.lei@canonical.com>
---
 drivers/net/usb/usbnet.c   |   13 ++++++++++++-
 include/linux/usb/usbnet.h |    2 +-
 2 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/drivers/net/usb/usbnet.c b/drivers/net/usb/usbnet.c
index e944109..e986e4b 100644
--- a/drivers/net/usb/usbnet.c
+++ b/drivers/net/usb/usbnet.c
@@ -677,6 +677,18 @@ static void usbnet_terminate_urbs(struct usbnet *dev)
 	remove_wait_queue(&unlink_wakeup, &wait);
 }
 
+void usbnet_link_change(struct usbnet *dev, int link, int need_reset)
+{
+	if (link)
+		netif_carrier_on(dev->net);
+	else
+		netif_carrier_off(dev->net);
+
+	if (need_reset && link)
+		usbnet_defer_kevent(dev, EVENT_LINK_RESET);
+}
+EXPORT_SYMBOL(usbnet_link_change);
+
 int usbnet_stop (struct net_device *net)
 {
 	struct usbnet		*dev = netdev_priv(net);
@@ -1591,7 +1603,6 @@ int usbnet_resume (struct usb_interface *intf)
 }
 EXPORT_SYMBOL_GPL(usbnet_resume);
 
-
 /*-------------------------------------------------------------------------*/
 
 static int __init usbnet_init(void)
diff --git a/include/linux/usb/usbnet.h b/include/linux/usb/usbnet.h
index f87cf62..1937b74 100644
--- a/include/linux/usb/usbnet.h
+++ b/include/linux/usb/usbnet.h
@@ -160,7 +160,7 @@ extern int usbnet_probe(struct usb_interface *, const struct usb_device_id *);
 extern int usbnet_suspend(struct usb_interface *, pm_message_t);
 extern int usbnet_resume(struct usb_interface *);
 extern void usbnet_disconnect(struct usb_interface *);
-
+extern void usbnet_link_change(struct usbnet *dev, int link, int need_reset);
 
 /* Drivers that reuse some of the standard USB CDC infrastructure
  * (notably, using multiple interfaces according to the CDC
-- 
1.7.9.5

[RFC PATCH v1 2/3] usbnet: apply usbnet_link_change

[Ming Lei]

This patch applies the introduce usbnet_link_change API.

Signed-off-by: Ming Lei <ming.lei-Z7WLFzj8eWMS+FvcfC7Uqw@public.gmane.org>
---
 drivers/net/usb/asix_devices.c |    6 +-----
 drivers/net/usb/cdc_ether.c    |    5 +----
 drivers/net/usb/cdc_ncm.c      |    9 +++------
 drivers/net/usb/dm9601.c       |    7 +------
 drivers/net/usb/mcs7830.c      |    6 +-----
 drivers/net/usb/sierra_net.c   |    3 +--
 drivers/net/usb/usbnet.c       |    2 +-
 7 files changed, 9 insertions(+), 29 deletions(-)

diff --git a/drivers/net/usb/asix_devices.c b/drivers/net/usb/asix_devices.c
index 4fd48df..c354bb1 100644
--- a/drivers/net/usb/asix_devices.c
+++ b/drivers/net/usb/asix_devices.c
@@ -55,11 +55,7 @@ static void asix_status(struct usbnet *dev, struct urb *urb)
 	event = urb->transfer_buffer;
 	link = event->link & 0x01;
 	if (netif_carrier_ok(dev->net) != link) {
-		if (link) {
-			netif_carrier_on(dev->net);
-			usbnet_defer_kevent (dev, EVENT_LINK_RESET );
-		} else
-			netif_carrier_off(dev->net);
+		usbnet_link_change(dev, link, 1);
 		netdev_dbg(dev->net, "Link Status is: %d\n", link);
 	}
 }
diff --git a/drivers/net/usb/cdc_ether.c b/drivers/net/usb/cdc_ether.c
index a03de71..c6e4be5 100644
--- a/drivers/net/usb/cdc_ether.c
+++ b/drivers/net/usb/cdc_ether.c
@@ -406,10 +406,7 @@ void usbnet_cdc_status(struct usbnet *dev, struct urb *urb)
 	case USB_CDC_NOTIFY_NETWORK_CONNECTION:
 		netif_dbg(dev, timer, dev->net, "CDC: carrier %s\n",
 			  event->wValue ? "on" : "off");
-		if (event->wValue)
-			netif_carrier_on(dev->net);
-		else
-			netif_carrier_off(dev->net);
+		usbnet_link_change(dev, event->wValue, 0);
 		break;
 	case USB_CDC_NOTIFY_SPEED_CHANGE:	/* tx/rx rates */
 		netif_dbg(dev, timer, dev->net, "CDC: speed change (len %d)\n",
diff --git a/drivers/net/usb/cdc_ncm.c b/drivers/net/usb/cdc_ncm.c
index 4cd582a..f425c2c 100644
--- a/drivers/net/usb/cdc_ncm.c
+++ b/drivers/net/usb/cdc_ncm.c
@@ -593,7 +593,7 @@ advance:
 	 * (carrier is OFF) during attach, so the IP network stack does not
 	 * start IPv6 negotiation and more.
 	 */
-	netif_carrier_off(dev->net);
+	usbnet_link_change(dev, 0, 0);
 	ctx->tx_speed = ctx->rx_speed = 0;
 	return 0;
 
@@ -1131,12 +1131,9 @@ static void cdc_ncm_status(struct usbnet *dev, struct urb *urb)
 			" %sconnected\n",
 			ctx->netdev->name, ctx->connected ? "" : "dis");
 
-		if (ctx->connected)
-			netif_carrier_on(dev->net);
-		else {
-			netif_carrier_off(dev->net);
+		usbnet_link_change(dev, ctx->connected, 0);
+		if (!ctx->connected)
 			ctx->tx_speed = ctx->rx_speed = 0;
-		}
 		break;
 
 	case USB_CDC_NOTIFY_SPEED_CHANGE:
diff --git a/drivers/net/usb/dm9601.c b/drivers/net/usb/dm9601.c
index e0433ce..7422d5a 100644
--- a/drivers/net/usb/dm9601.c
+++ b/drivers/net/usb/dm9601.c
@@ -587,12 +587,7 @@ static void dm9601_status(struct usbnet *dev, struct urb *urb)
 
 	link = !!(buf[0] & 0x40);
 	if (netif_carrier_ok(dev->net) != link) {
-		if (link) {
-			netif_carrier_on(dev->net);
-			usbnet_defer_kevent (dev, EVENT_LINK_RESET);
-		}
-		else
-			netif_carrier_off(dev->net);
+		usbnet_link_change(dev, link, 1);
 		netdev_dbg(dev->net, "Link Status is: %d\n", link);
 	}
 }
diff --git a/drivers/net/usb/mcs7830.c b/drivers/net/usb/mcs7830.c
index 03c2d8d..49a98b7 100644
--- a/drivers/net/usb/mcs7830.c
+++ b/drivers/net/usb/mcs7830.c
@@ -639,11 +639,7 @@ static void mcs7830_status(struct usbnet *dev, struct urb *urb)
 
 	link = !(buf[1] & 0x20);
 	if (netif_carrier_ok(dev->net) != link) {
-		if (link) {
-			netif_carrier_on(dev->net);
-			usbnet_defer_kevent(dev, EVENT_LINK_RESET);
-		} else
-			netif_carrier_off(dev->net);
+		usbnet_link_change(dev, link, 1);
 		netdev_dbg(dev->net, "Link Status is: %d\n", link);
 	}
 }
diff --git a/drivers/net/usb/sierra_net.c b/drivers/net/usb/sierra_net.c
index 7ae70e9..08ed9e5 100644
--- a/drivers/net/usb/sierra_net.c
+++ b/drivers/net/usb/sierra_net.c
@@ -414,11 +414,10 @@ static void sierra_net_handle_lsi(struct usbnet *dev, char *data,
 	if (link_up) {
 		sierra_net_set_ctx_index(priv, hh->msgspecific.byte);
 		priv->link_up = 1;
-		netif_carrier_on(dev->net);
 	} else {
 		priv->link_up = 0;
-		netif_carrier_off(dev->net);
 	}
+	usbnet_link_change(dev, link_up, 0);
 }
 
 static void sierra_net_dosync(struct usbnet *dev)
diff --git a/drivers/net/usb/usbnet.c b/drivers/net/usb/usbnet.c
index e986e4b..dc4ff47 100644
--- a/drivers/net/usb/usbnet.c
+++ b/drivers/net/usb/usbnet.c
@@ -1499,7 +1499,7 @@ usbnet_probe (struct usb_interface *udev, const struct usb_device_id *prod)
 	netif_device_attach (net);
 
 	if (dev->driver_info->flags & FLAG_LINK_INTR)
-		netif_carrier_off(net);
+		usbnet_link_change(dev, 0, 0);
 
 	return 0;
 
-- 
1.7.9.5

--
To unsubscribe from this list: send the line "unsubscribe linux-usb" in
the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

[RFC PATCH v1 3/3] usbnet: support runtime PM triggered by link change

[Ming Lei]

This patch implements runtime PM triggered by link change event
for devices which haven't defined manage_power() callback, based
on the below consideration:

- this kind of runtime PM has been supported by some PCI network
interfaces already, and it does make sense to suspend the usb
device to save power if no link is detected

- link down triggered runtime needn't to be implemented for devices
which have already supported traffic based runtime PM by .manage_power,
because runtime suspend can be triggered when no tx frames are to be
transmitted after link becoms down.

Unfortunately, some usbnet devices don't support remote wakeup,
or some devices may support it but the remote wakup can't be enabled
for link change event for some reason(no documents are public, not
supported ...).

This patch takes a periodic timer to wake up devices for detecting
the link change event if remote wakeup by link change can't be
supported. If the link is found to be down, put the device into
suspend immediately.

For the devices which support remote wakeup by link change and
don't support remote wakeup by incoming packets(not implement
manage_power callback), the patch can still make link change
triggered runtime PM working on these devices.

Signed-off-by: Ming Lei <ming.lei-Z7WLFzj8eWMS+FvcfC7Uqw@public.gmane.org>
---
 drivers/net/usb/sierra_net.c |    3 +-
 drivers/net/usb/usbnet.c     |  269 +++++++++++++++++++++++++++++++++++++++++-
 include/linux/usb/usbnet.h   |   20 ++++
 3 files changed, 286 insertions(+), 6 deletions(-)

diff --git a/drivers/net/usb/sierra_net.c b/drivers/net/usb/sierra_net.c
index 08ed9e5..0993f2d 100644
--- a/drivers/net/usb/sierra_net.c
+++ b/drivers/net/usb/sierra_net.c
@@ -418,6 +418,7 @@ static void sierra_net_handle_lsi(struct usbnet *dev, char *data,
 		priv->link_up = 0;
 	}
 	usbnet_link_change(dev, link_up, 0);
+	usbnet_link_updated(dev);
 }
 
 static void sierra_net_dosync(struct usbnet *dev)
@@ -915,7 +916,7 @@ static struct sk_buff *sierra_net_tx_fixup(struct usbnet *dev,
 
 static const struct driver_info sierra_net_info_direct_ip = {
 	.description = "Sierra Wireless USB-to-WWAN Modem",
-	.flags = FLAG_WWAN | FLAG_SEND_ZLP,
+	.flags = FLAG_WWAN | FLAG_SEND_ZLP | FLAG_LINK_UPDATE_BY_DRIVER,
 	.bind = sierra_net_bind,
 	.unbind = sierra_net_unbind,
 	.status = sierra_net_status,
diff --git a/drivers/net/usb/usbnet.c b/drivers/net/usb/usbnet.c
index dc4ff47..14aa39e 100644
--- a/drivers/net/usb/usbnet.c
+++ b/drivers/net/usb/usbnet.c
@@ -91,6 +91,12 @@ static int msg_level = -1;
 module_param (msg_level, int, 0);
 MODULE_PARM_DESC (msg_level, "Override default message level");
 
+/* link runtime PM: auto check time */
+static int link_autocheck_time = 3;
+module_param_named(autocheck, link_autocheck_time, int, 0644);
+MODULE_PARM_DESC(autocheck, "default link auto check time in second");
+
+
 /*-------------------------------------------------------------------------*/
 
 /* handles CDC Ethernet and many other network "bulk data" interfaces */
@@ -677,8 +683,228 @@ static void usbnet_terminate_urbs(struct usbnet *dev)
 	remove_wait_queue(&unlink_wakeup, &wait);
 }
 
-void usbnet_link_change(struct usbnet *dev, int link, int need_reset)
+void usbnet_link_updated(struct usbnet *dev)
+{
+	complete(&dev->link_update_completion);
+}
+EXPORT_SYMBOL(usbnet_link_updated);
+
+#define usbnet_link_suspend(dev) do { \
+	dev_dbg(&dev->intf->dev, "%s:link suspend", __func__); \
+	usb_autopm_put_interface_async(dev->intf); \
+} while(0)
+
+#define usbnet_link_resume(dev) do { \
+	dev_dbg(&dev->intf->dev, "%s:link resume", __func__); \
+	usb_autopm_get_interface_async(dev->intf); \
+} while(0)
+
+static int need_link_runtime_pm(struct usbnet *dev)
+{
+	if (dev->driver_info->manage_power)
+		return 0;
+
+	if (!dev->driver_info->status)
+		return 0;
+
+	return 1;
+}
+
+/* called by usbnet_suspend */
+static void start_link_detect(struct usbnet *dev)
 {
+	if (!dev->link_rpm_enabled)
+		return;
+
+	if (dev->link_remote_wakeup)
+		return;
+
+	if (dev->link_check_started)
+		return;
+
+	dev->link_check_started = 1;
+	queue_delayed_work(system_freezable_wq, &dev->link_detect_work,
+			   link_autocheck_time * HZ);
+}
+
+/* called by usbnet_resume */
+static void end_link_detect(struct usbnet *dev, int force_cancel)
+{
+	if (!dev->link_rpm_enabled)
+		return;
+
+	if (!dev->link_check_started)
+		return;
+
+	/*
+	 * cancel the link detect work if usbnet is resumed
+	 * not by link detect work
+	 */
+	if (!dev->link_checking || force_cancel)
+		cancel_delayed_work_sync(&dev->link_detect_work);
+
+	dev->link_check_started = 0;
+}
+
+/* called by usbnet_open */
+static void enable_link_runtime_pm(struct usbnet *dev)
+{
+	dev->link_rpm_enabled = 1;
+
+	if (!dev->link_remote_wakeup) {
+		spin_lock_irq(&dev->udev->dev.power.lock);
+		dev->old_autosuspend_delay =
+			dev->udev->dev.power.autosuspend_delay;
+		spin_unlock_irq(&dev->udev->dev.power.lock);
+		pm_runtime_set_autosuspend_delay(&dev->udev->dev, 1);
+	} else {
+		dev->intf->needs_remote_wakeup = 1;
+	}
+
+	if (!netif_carrier_ok(dev->net) && dev->link_rpm_supported) {
+		dev->link_open_suspend = 1;
+		usbnet_link_suspend(dev);
+	}
+}
+
+/* called by usbnet_stop */
+static void disable_link_runtime_pm(struct usbnet *dev)
+{
+	int delay;
+
+	if (!dev->link_rpm_enabled)
+		return;
+
+	dev->link_rpm_enabled = 0;
+	end_link_detect(dev, 1);
+
+	if (dev->link_open_suspend) {
+		usbnet_link_resume(dev);
+		dev->link_open_suspend = 0;
+	}
+
+	if (dev->link_remote_wakeup) {
+		dev->intf->needs_remote_wakeup = 0;
+		return;
+	}
+
+	spin_lock_irq(&dev->udev->dev.power.lock);
+	delay = dev->udev->dev.power.autosuspend_delay;
+	spin_unlock_irq(&dev->udev->dev.power.lock);
+
+	/*
+	 * If autosuspend delay has been changed after
+	 * enable_link_runtime_pm(), just keep the latest delay.
+	 *
+	 * FIXME: the delay might be changed after the above
+	 * lock is released and before the lock is held in
+	 * pm_runtime_set_autosuspend_delay(), looks no
+	 * big effect.
+	 */
+	if (delay == 1) {
+		delay = dev->old_autosuspend_delay;
+		pm_runtime_set_autosuspend_delay(&dev->udev->dev,
+						 delay);
+	}
+}
+
+static void update_link_state(struct usbnet *dev)
+{
+	char		*buf = NULL;
+	unsigned	pipe = 0;
+	unsigned	maxp;
+	int		ret, act_len, timeout;
+	struct urb	urb;
+
+	pipe = usb_rcvintpipe(dev->udev,
+			      dev->status->desc.bEndpointAddress
+				& USB_ENDPOINT_NUMBER_MASK);
+	maxp = usb_maxpacket(dev->udev, pipe, 0);
+
+	/*
+	 * Take default timeout as 2 times of period.
+	 * It is observed that asix device can update its link
+	 * state duing one period(128ms). Low level driver can set
+	 * its default update link time in bind() callback.
+	 */
+	if (!dev->link_update_timeout) {
+		timeout = max((int) dev->status->desc.bInterval,
+			(dev->udev->speed == USB_SPEED_HIGH) ? 7 : 3);
+		timeout = 1 << timeout;
+		if (dev->udev->speed == USB_SPEED_HIGH)
+			timeout /= 8;
+		if (timeout < 128)
+			timeout = 128;
+	} else
+		timeout = dev->link_update_timeout;
+
+	buf = kmalloc(maxp, GFP_KERNEL);
+	if (!buf)
+		return;
+
+	dev_dbg(&dev->intf->dev, "%s: timeout %dms\n", __func__, timeout);
+	ret = usb_interrupt_msg(dev->udev, pipe, buf, maxp,
+			&act_len, timeout);
+	if (!ret) {
+		urb.status = 0;
+		urb.actual_length = act_len;
+		urb.transfer_buffer = buf;
+		urb.transfer_buffer_length = maxp;
+		dev->driver_info->status(dev, &urb);
+		if (dev->driver_info->flags &
+		    FLAG_LINK_UPDATE_BY_DRIVER)
+			wait_for_completion(&dev->link_update_completion);
+		dev_dbg(&dev->intf->dev, "%s: link updated\n", __func__);
+	} else
+		dev_dbg(&dev->intf->dev, "%s: link update failed %d\n",
+				__func__, ret);
+	kfree(buf);
+}
+
+static void link_detect_work(struct work_struct *work)
+{
+	struct usbnet	*dev = container_of(work, struct usbnet,
+					    link_detect_work.work);
+
+	dev_dbg(&dev->intf->dev, "%s: link resume\n", __func__);
+
+	dev->link_checking = 1;
+	usb_autopm_get_interface(dev->intf);
+	update_link_state(dev);
+	dev->link_checking = 0;
+
+	dev_dbg(&dev->intf->dev, "%s: link state %d\n",
+		__func__, netif_carrier_ok(dev->net));
+
+	if (!netif_carrier_ok(dev->net))
+		usb_autopm_put_interface(dev->intf);
+	else
+		usb_submit_urb(dev->interrupt, GFP_NOIO);
+}
+
+static void init_link_rpm(struct usbnet *dev)
+{
+	INIT_DELAYED_WORK(&dev->link_detect_work, link_detect_work);
+	init_completion(&dev->link_update_completion);
+
+	dev->link_remote_wakeup = !!(dev->driver_info->flags &
+				  FLAG_LINK_SUPPORT_REMOTE_WAKEUP);
+	if (dev->link_remote_wakeup &&
+	    !device_can_wakeup(&dev->udev->dev)) {
+		dev_err(&dev->udev->dev,
+			"I don't support remote wakeup\n");
+		dev->link_remote_wakeup = 0;
+	}
+
+	dev->link_state = 1;
+}
+
+static void __usbnet_link_change(struct usbnet *dev, int link,
+				 int need_reset)
+{
+	dev_dbg(&dev->intf->dev, "%s: old_link=%d link=%d\n", __func__,
+		dev->link_state, link);
+
 	if (link)
 		netif_carrier_on(dev->net);
 	else
@@ -686,6 +912,25 @@ void usbnet_link_change(struct usbnet *dev, int link, int need_reset)
 
 	if (need_reset && link)
 		usbnet_defer_kevent(dev, EVENT_LINK_RESET);
+
+	if (dev->link_rpm_enabled) {
+		if (!link && dev->link_state)
+			usbnet_link_suspend(dev);
+		else if (link && !dev->link_state && dev->link_remote_wakeup)
+			usbnet_link_resume(dev);
+	}
+	dev->link_state = link;
+}
+
+void usbnet_link_change(struct usbnet *dev, int link, int need_reset)
+{
+	/*
+	 * Suppose the low level driver may support link runtime PM
+	 * if it can detect the link change via usbnet_link_change.
+	 */
+	dev->link_rpm_supported = 1;
+
+	__usbnet_link_change(dev, link, need_reset);
 }
 EXPORT_SYMBOL(usbnet_link_change);
 
@@ -731,8 +976,10 @@ int usbnet_stop (struct net_device *net)
 	tasklet_kill (&dev->bh);
 	if (info->manage_power)
 		info->manage_power(dev, 0);
-	else
+	else {
+		disable_link_runtime_pm(dev);
 		usb_autopm_put_interface(dev->intf);
+	}
 
 	return 0;
 }
@@ -807,6 +1054,9 @@ int usbnet_open (struct net_device *net)
 		if (retval < 0)
 			goto done_manage_power_error;
 		usb_autopm_put_interface(dev->intf);
+	} else {
+		if (need_link_runtime_pm(dev))
+			enable_link_runtime_pm(dev);
 	}
 	return retval;
 
@@ -1499,7 +1749,9 @@ usbnet_probe (struct usb_interface *udev, const struct usb_device_id *prod)
 	netif_device_attach (net);
 
 	if (dev->driver_info->flags & FLAG_LINK_INTR)
-		usbnet_link_change(dev, 0, 0);
+		__usbnet_link_change(dev, 0, 0);
+
+	init_link_rpm(dev);
 
 	return 0;
 
@@ -1550,6 +1802,9 @@ int usbnet_suspend (struct usb_interface *intf, pm_message_t message)
 		 * wake the device
 		 */
 		netif_device_attach (dev->net);
+
+		if (PMSG_IS_AUTO(message))
+			start_link_detect(dev);
 	}
 	return 0;
 }
@@ -1564,8 +1819,10 @@ int usbnet_resume (struct usb_interface *intf)
 
 	if (!--dev->suspend_count) {
 		/* resume interrupt URBs */
-		if (dev->interrupt && test_bit(EVENT_DEV_OPEN, &dev->flags))
-			usb_submit_urb(dev->interrupt, GFP_NOIO);
+		if (dev->interrupt && test_bit(EVENT_DEV_OPEN, &dev->flags)) {
+			if (!dev->link_checking)
+				usb_submit_urb(dev->interrupt, GFP_NOIO);
+		}
 
 		spin_lock_irq(&dev->txq.lock);
 		while ((res = usb_get_from_anchor(&dev->deferred))) {
@@ -1598,6 +1855,8 @@ int usbnet_resume (struct usb_interface *intf)
 				netif_tx_wake_all_queues(dev->net);
 			tasklet_schedule (&dev->bh);
 		}
+
+		end_link_detect(dev, 0);
 	}
 	return 0;
 }
diff --git a/include/linux/usb/usbnet.h b/include/linux/usb/usbnet.h
index 1937b74..d23dae5 100644
--- a/include/linux/usb/usbnet.h
+++ b/include/linux/usb/usbnet.h
@@ -68,6 +68,19 @@ struct usbnet {
 #		define EVENT_RX_PAUSED	5
 #		define EVENT_DEV_ASLEEP 6
 #		define EVENT_DEV_OPEN	7
+
+	/* link down triggered runtime PM */
+	struct delayed_work	link_detect_work;
+	struct completion	link_update_completion;
+	int			link_update_timeout;
+	int			old_autosuspend_delay;
+	unsigned int		link_rpm_supported:1;
+	unsigned int		link_rpm_enabled:1;
+	unsigned int		link_check_started:1;
+	unsigned int		link_checking:1;
+	unsigned int		link_open_suspend:1;
+	unsigned int		link_state:1;
+	unsigned int		link_remote_wakeup:1;
 };
 
 static inline struct usb_driver *driver_of(struct usb_interface *intf)
@@ -106,6 +119,12 @@ struct driver_info {
 #define FLAG_MULTI_PACKET	0x2000
 #define FLAG_RX_ASSEMBLE	0x4000	/* rx packets may span >1 frames */
 
+/* some drivers may not update link state in .status */
+#define FLAG_LINK_UPDATE_BY_DRIVER	0x8000
+
+/* device support remote wakeup by link change */
+#define FLAG_LINK_SUPPORT_REMOTE_WAKEUP	0x10000
+
 	/* init device ... can sleep, or cause probe() failure */
 	int	(*bind)(struct usbnet *, struct usb_interface *);
 
@@ -161,6 +180,7 @@ extern int usbnet_suspend(struct usb_interface *, pm_message_t);
 extern int usbnet_resume(struct usb_interface *);
 extern void usbnet_disconnect(struct usb_interface *);
 extern void usbnet_link_change(struct usbnet *dev, int link, int need_reset);
+extern void usbnet_link_updated(struct usbnet *dev);
 
 /* Drivers that reuse some of the standard USB CDC infrastructure
  * (notably, using multiple interfaces according to the CDC
-- 
1.7.9.5

--
To unsubscribe from this list: send the line "unsubscribe linux-usb" in
the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Re: [RFC PATCH v1 0/3] usbnet: runtime suspend when link becomes down

[Oliver Neukum]

On Tuesday 18 September 2012 22:23:18 Ming Lei wrote:
> Hi,
> 
> Currently only very few usbnet devices support the traffic based
> runtime PM, eg. wake up devices if there are packets to be transmitted.

Hi,

independent of the rest it seems to me that the first two patches in your
series are a useful cleanup by themselves. Could you submit them separately?

	Regards
		Oliver

--
To unsubscribe from this list: send the line "unsubscribe linux-usb" in
the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Re: [RFC PATCH v1 0/3] usbnet: runtime suspend when link becomes down

[Ming Lei]

On Tue, Sep 18, 2012 at 10:28 PM, Oliver Neukum <oneukum@suse.de> wrote:
> On Tuesday 18 September 2012 22:23:18 Ming Lei wrote:
>> Hi,
>>
>> Currently only very few usbnet devices support the traffic based
>> runtime PM, eg. wake up devices if there are packets to be transmitted.
>
> Hi,
>
> independent of the rest it seems to me that the first two patches in your
> series are a useful cleanup by themselves. Could you submit them separately?

IMO, if the first two are OK now, David may commit the first two only.

Thanks,
--
Ming Lei

Re: [RFC PATCH v1 1/3] usbnet: introduce usbnet_link_change API

[Oliver Neukum]

On Tuesday 18 September 2012 22:23:19 Ming Lei wrote:
> This patch introduces the API of usbnet_link_change, so that
> usbnet can trace the link change, which may help to implement
> the later runtime PM triggered by usb ethernet link change.
> 
> Signed-off-by: Ming Lei <ming.lei-Z7WLFzj8eWMS+FvcfC7Uqw@public.gmane.org>
Acked-by: Oliver Neukum <oneukum-l3A5Bk7waGM@public.gmane.org>

	Regards
		Oliver

--
To unsubscribe from this list: send the line "unsubscribe linux-usb" in
the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Re: [RFC PATCH v1 2/3] usbnet: apply usbnet_link_change

[Oliver Neukum]

On Tuesday 18 September 2012 22:23:20 Ming Lei wrote:
> This patch applies the introduce usbnet_link_change API.
> 
> Signed-off-by: Ming Lei <ming.lei@canonical.com>
Acked-by: Oliver Neukum <oneukum@suse.de>

	Regards
		Oliver

Re: [RFC PATCH v1 1/3] usbnet: introduce usbnet_link_change API

[David Miller]

From: Ming Lei <ming.lei-Z7WLFzj8eWMS+FvcfC7Uqw@public.gmane.org>
Date: Tue, 18 Sep 2012 22:23:19 +0800

> +void usbnet_link_change(struct usbnet *dev, int link, int need_reset)

Please use 'bool' for link and need_reset.
--
To unsubscribe from this list: send the line "unsubscribe linux-usb" in
the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html