Re: [linux-pm] [PATCH 0/8] Suspend block api (version 6)

From: Rafael J. Wysocki
Date: Thu May 13 2010 - 17:55:12 EST


On Thursday 13 May 2010, Tony Lindgren wrote:
> * Rafael J. Wysocki <rjw@xxxxxxx> [100513 14:16]:
> > On Thursday 13 May 2010, Matthew Garrett wrote:
> > > On Thu, May 13, 2010 at 01:23:20PM -0700, Tony Lindgren wrote:
> > > > * Matthew Garrett <mjg@xxxxxxxxxx> [100513 13:03]:
> > > > > On Thu, May 13, 2010 at 01:00:04PM -0700, Tony Lindgren wrote:
> > > > >
> > > > > > The system stays running because there's something to do. The system
> > > > > > won't suspend until all the processors hit the kernel idle loop and
> > > > > > the next_timer_interrupt_critical() returns nothing.
> > > > >
> > > > > At which point an application in a busy loop cripples you.
> > > >
> > > > Maybe you could deal with the misbehaving untrusted apps in the userspace
> > > > by sending kill -STOP to them when the screen blanks? Then continue
> > > > when some event wakes up the system again.
> > >
> > > And if that's the application that's listening to the network socket
> > > that you want to get a wakeup event from? This problem is hard. I'd love
> > > there to be an elegant solution based on using the scheduler, but I
> > > really don't know what it is.
> >
> > I agree and I don't understand the problem that people have with the
> > opportunistic suspend feature.
>
> It seems to be picking quite a few comments for one.
>
> > It solves a practical issue that _at_ _the_ _moment_ cannot be solved
> > differently, while there's a growing number of out-of-tree drivers depending
> > on this framework. We need those drivers in and because we don't have any
> > viable alternative at hand, we have no good reason to reject it.
>
> Nothing is preventing merging the drivers can be merged without
> these calls.

And yet, there _is_ a growing nuber of drivers that don't get merge because
of that. That's _reality_. Are you going to discuss with facts, or what?

Rafael
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