Message-ID: <1450867558.6437.10.camel@suse.com>
Subject: Re: [PATCH v2] r8152: fix lockup when runtime PM is enabled
From: Oliver Neukum <oneukum@suse.com>
To: Hayes Wang <hayeswang@realtek.com>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>,
        "netdev@vger.kernel.org" <netdev@vger.kernel.org>,
        "peter@lekensteyn.nl" <peter@lekensteyn.nl>
Date: Wed, 23 Dec 2015 11:45:58 +0100
In-Reply-To: <0835B3720019904CB8F7AA43166CEEB2F9547E@RTITMBSV03.realtek.com.tw>
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On Wed, 2015-12-23 at 09:20 +0000, Hayes Wang wrote:
> Oliver Neukum [mailto:oneukum@suse.de]
> > Sent: Wednesday, December 23, 2015 4:20 PM
> [...]
> > No, step (2) does not exist. Calls to suspend() and [reset_]resume()
> > always balance. Usually a driver shouldn't care about system suspend.
> > The way the driver is currently coded will also fail for Port-Power Off.
> 
> It is different with Windows. The Windows would resume the device before
> system suspend, if the system suspend follows the autosuspend.
> 
> Would this be a problem? After system suspend, the device may wake up
> the system when receiving any packet, not only magic packet. The wake
> events are different for system suspend and autosuspend. However, I
> couldn't change the wake event, because the autosuspend occurs first,
> and the suspend() is only called once.

That is indeed a problem and I need to think a bit about finding
a good solution. If you are happy with an inelegant solution, you can
use a pm_notifier, which will tell you that the system is going
to suspend. This is documented:

https://www.kernel.org/doc/Documentation/power/notifiers.txt

	HTH
		Oliver


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