From: "Rafael J. Wysocki" <rjw@sisk.pl>
To: =?utf-8?q?Bart=C5=82omiej_Zimo=C5=84?= <uzi18@o2.pl>
Subject: Re: [linux-pm] [suspend/resume] Re: userspace notification from module
Date: Tue, 5 Jan 2010 22:23:21 +0100
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Cc: linux-kernel@vger.kernel.org, Anders Eriksson <aeriksson@fastmail.fm>,
       linux-pm@lists.linux-foundation.org, awalls@radix.net,
       danborkmann@googlemail.com
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On Tuesday 05 January 2010, Bartłomiej Zimoń wrote:
> Dnia 5 stycznia 2010 10:07 	Anders Eriksson <aeriksson@fastmail.fm> napisał(a):
> > 
> > rjw@sisk.pl said:
> > >> > I don't see a problem with this in principle, although I don't think signals
> > >> > are very suitable for this particular purpose, because you need two-way
> > >> > communication between the power manager and the processes it's going to
> > >> > notify (because it has to wait for the processes to finish their preparations
> > >> > and to tell it that they are ready). 
> > 
> > Wouldn't there need to be dependecy tracking for the userspace processes? A 
> > process couldn't signal "done" until it know there's no more work to do, which 
> > requires all other processes to finish up first.
> > 
> 
> Not all processes will need pm notification.
> 
> Just in case, could this "power manager" be provided as userspace
> driver for kernel (for example compiled as UIO)?

I don't really understand why you want to do that in the kernel.  Is there
any particular reason why this cannot be done in the user space?

Rafael
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