netdev - Dealing nicely with PM failure

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Date:	Fri, 14 Dec 2012 15:56:26 +0100
From:	Oliver Neukum <oneukum@...e.de>
To:	Ming Lei <ming.lei@...onical.com>,
	Steve Glendinning <steve@...well.net>, netdev@...r.kernel.org
Subject: Dealing nicely with PM failure

Hi,

this question about the smsc devices gave me an idea.
How about this?

>From f1bdff89eea4c10102f867f9f22cb2b60519e425 Mon Sep 17 00:00:00 2001
From: Oliver Neukum <oliver@...kum.org>
Date: Fri, 14 Dec 2012 15:51:36 +0100
Subject: [PATCH] usbnet: handle PM failure gracefully

If a device fails to do remote wakeup, this is no reason
to abort an open totally. This patch just continues without
runtime PM.

Signed-off-by: Oliver Neukum <oneukum@...e.de>
---
 drivers/net/usb/usbnet.c   |   17 +++++++++--------
 include/linux/usb/usbnet.h |    1 +
 2 files changed, 10 insertions(+), 8 deletions(-)

diff --git a/drivers/net/usb/usbnet.c b/drivers/net/usb/usbnet.c
index c04110b..2010eef 100644
--- a/drivers/net/usb/usbnet.c
+++ b/drivers/net/usb/usbnet.c
@@ -719,7 +719,8 @@ int usbnet_stop (struct net_device *net)
 	dev->flags = 0;
 	del_timer_sync (&dev->delay);
 	tasklet_kill (&dev->bh);
-	if (info->manage_power)
+	if (info->manage_power &&
+	    !test_and_clear_bit(EVENT_NO_RUNTIME_PM, &dev->flags))
 		info->manage_power(dev, 0);
 	else
 		usb_autopm_put_interface(dev->intf);
@@ -793,15 +794,15 @@ int usbnet_open (struct net_device *net)
 	// delay posting reads until we're fully open
 	tasklet_schedule (&dev->bh);
 	if (info->manage_power) {
-		retval = info->manage_power(dev, 1);
-		if (retval < 0)
-			goto done_manage_power_error;
-		usb_autopm_put_interface(dev->intf);
+		int r;
+
+		r = info->manage_power(dev, 1);
+		if (r < 0)
+			set_bit(EVENT_NO_RUNTIME_PM, &dev->flags);
+		else
+			usb_autopm_put_interface(dev->intf);
 	}
 	return retval;
-
-done_manage_power_error:
-	clear_bit(EVENT_DEV_OPEN, &dev->flags);
 done:
 	usb_autopm_put_interface(dev->intf);
 done_nopm:
diff --git a/include/linux/usb/usbnet.h b/include/linux/usb/usbnet.h
index 9bbeabf..288b32a 100644
--- a/include/linux/usb/usbnet.h
+++ b/include/linux/usb/usbnet.h
@@ -69,6 +69,7 @@ struct usbnet {
 #		define EVENT_DEV_ASLEEP 6
 #		define EVENT_DEV_OPEN	7
 #		define EVENT_DEVICE_REPORT_IDLE	8
+#		define EVENT_NO_RUNTIME_PM	9
 };
 
 static inline struct usb_driver *driver_of(struct usb_interface *intf)
-- 
1.7.7


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