Subject: =?UTF-8?Q?Re:_[suspend/resume]_Re:_userspace_notification_from_module?=
From: =?UTF-8?Q?Bart=C5=82omiej_Zimo=C5=84?= <uzi18@o2.pl>
To: linux-kernel@vger.kernel.org
Cc: =?UTF-8?Q?Andy_Walls?= <awalls@radix.net>,
       =?UTF-8?Q?Daniel_Borkmann?= <danborkmann@googlemail.com>,
       linux-kernel@vger.kernel.org,
       =?UTF-8?Q?pm_list?= <linux-pm@lists.linux-foundation.org>,
       =?UTF-8?Q?Alan_Stern?= <stern@rowland.harvard.edu>
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Date: Sun, 03 Jan 2010 18:20:44 +0100
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Dnia 3 stycznia 2010 0:29 	"Rafael J. Wysocki" <rjw@sisk.pl> napisał(a):
> > - could be even used partialy by pm-utils
> > - it is perfect just to notify about event
> 
> OK, but why exactly do _you_ need that to happen?
> 
> There's one important drawback of making the kernel generate the notification.
> Namely, even if your userspace task is notified by the kernel of a PM event,
> that doesn't mean it'll have the time to act upon that, because the kernel will
> attempt to freeze it right after the notification has been sent.  This means
> you'd need a way to make the kernel wait for your user space process to finish
> it's job before continuing the suspend/hibernate process.  Otherwise it's not
> going to be very useful.
> 

So if it is bad idea, we could create more advenced implementation.
i.e. IPC or callbacks for this kind of events.

There is vision in my mind to have alternative to pm-utils, 
but even more powerfull and easy to implement in program.
I could try to implement something like that.

Rafael i'm open for Your suggestions.

Best regards.
Bartłomiej Zimoń
PLD Linux, Kadu Team, FreeRunner user
http://kadu-im.blogspot.com/

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