5 files changed, 23 insertions, 19 deletions

diff --git a/drivers/net/usb/cdc_mbim.c b/drivers/net/usb/cdc_mbim.c
index c964544..8728198 100644
--- a/drivers/net/usb/cdc_mbim.c
+++ b/drivers/net/usb/cdc_mbim.c
@@ -323,6 +323,11 @@ static int cdc_mbim_suspend(struct usb_interface *intf, pm_message_t message)
 		goto error;
 	}
 
+	/*
+	 * Both usbnet_suspend() and subdriver->suspend() MUST return 0
+	 * in system sleep context, otherwise, the resume callback has
+	 * to recover device from previous suspend failure.
+	 */
 	ret = usbnet_suspend(intf, message);
 	if (ret < 0)
 		goto error;
diff --git a/drivers/net/usb/hso.c b/drivers/net/usb/hso.c
index e2dd324..cba1d46 100644
--- a/drivers/net/usb/hso.c
+++ b/drivers/net/usb/hso.c
@@ -1925,7 +1925,6 @@ static void hso_std_serial_write_bulk_callback(struct urb *urb)
 {
 	struct hso_serial *serial = urb->context;
 	int status = urb->status;
-	struct tty_struct *tty;
 
 	/* sanity check */
 	if (!serial) {
@@ -1941,11 +1940,7 @@ static void hso_std_serial_write_bulk_callback(struct urb *urb)
 		return;
 	}
 	hso_put_activity(serial->parent);
-	tty = tty_port_tty_get(&serial->port);
-	if (tty) {
-		tty_wakeup(tty);
-		tty_kref_put(tty);
-	}
+	tty_port_tty_wakeup(&serial->port);
 	hso_kick_transmit(serial);
 
 	D1(" ");
@@ -2008,12 +2003,8 @@ static void ctrl_callback(struct urb *urb)
 		put_rxbuf_data_and_resubmit_ctrl_urb(serial);
 		spin_unlock(&serial->serial_lock);
 	} else {
-		struct tty_struct *tty = tty_port_tty_get(&serial->port);
 		hso_put_activity(serial->parent);
-		if (tty) {
-			tty_wakeup(tty);
-			tty_kref_put(tty);
-		}
+		tty_port_tty_wakeup(&serial->port);
 		/* response to a write command */
 		hso_kick_transmit(serial);
 	}
@@ -3133,18 +3124,13 @@ static void hso_serial_ref_free(struct kref *ref)
 static void hso_free_interface(struct usb_interface *interface)
 {
 	struct hso_serial *hso_dev;
-	struct tty_struct *tty;
 	int i;
 
 	for (i = 0; i < HSO_SERIAL_TTY_MINORS; i++) {
 		if (serial_table[i] &&
 		    (serial_table[i]->interface == interface)) {
 			hso_dev = dev2ser(serial_table[i]);
-			tty = tty_port_tty_get(&hso_dev->port);
-			if (tty) {
-				tty_hangup(tty);
-				tty_kref_put(tty);
-			}
+			tty_port_tty_hangup(&hso_dev->port, false);
 			mutex_lock(&hso_dev->parent->mutex);
 			hso_dev->parent->usb_gone = 1;
 			mutex_unlock(&hso_dev->parent->mutex);
diff --git a/drivers/net/usb/qmi_wwan.c b/drivers/net/usb/qmi_wwan.c
index 2a3579f..5a88e72 100644
--- a/drivers/net/usb/qmi_wwan.c
+++ b/drivers/net/usb/qmi_wwan.c
@@ -374,6 +374,11 @@ static int qmi_wwan_suspend(struct usb_interface *intf, pm_message_t message)
 	struct qmi_wwan_state *info = (void *)&dev->data;
 	int ret;
 
+	/*
+	 * Both usbnet_suspend() and subdriver->suspend() MUST return 0
+	 * in system sleep context, otherwise, the resume callback has
+	 * to recover device from previous suspend failure.
+	 */
 	ret = usbnet_suspend(intf, message);
 	if (ret < 0)
 		goto err;
diff --git a/drivers/net/usb/smsc75xx.c b/drivers/net/usb/smsc75xx.c
index 1a15ec1..75409748c 100644
--- a/drivers/net/usb/smsc75xx.c
+++ b/drivers/net/usb/smsc75xx.c
@@ -2015,7 +2015,11 @@ static int smsc75xx_suspend(struct usb_interface *intf, pm_message_t message)
 	ret = smsc75xx_enter_suspend0(dev);
 
 done:
-	if (ret)
+	/*
+	 * TODO: resume() might need to handle the suspend failure
+	 * in system sleep
+	 */
+	if (ret && PMSG_IS_AUTO(message))
 		usbnet_resume(intf);
 	return ret;
 }
diff --git a/drivers/net/usb/smsc95xx.c b/drivers/net/usb/smsc95xx.c
index e6d2dea..3f38ba8 100644
--- a/drivers/net/usb/smsc95xx.c
+++ b/drivers/net/usb/smsc95xx.c
@@ -1660,7 +1660,11 @@ static int smsc95xx_suspend(struct usb_interface *intf, pm_message_t message)
 	ret = smsc95xx_enter_suspend0(dev);
 
 done:
-	if (ret)
+	/*
+	 * TODO: resume() might need to handle the suspend failure
+	 * in system sleep
+	 */
+	if (ret && PMSG_IS_AUTO(message))
 		usbnet_resume(intf);
 	return ret;
 }