Re: [PATCH 0/8] Suspend block api (version 7)

["Rafael J. Wysocki" <rjw@sisk.pl>]

On Monday 17 May 2010, Brian Swetland wrote:
> On Mon, May 17, 2010 at 1:40 PM, Rafael J. Wysocki <rjw@sisk.pl> wrote:
> > On Monday 17 May 2010, Arve Hjønnevåg wrote:
> >>
> >> It should get out of that loop as soon as someone blocks suspend. If
> >> someone is constantly aborting suspend without using a suspend blocker
> >> it will be very inefficient, but it should still work.
> >
> > Well, the scenario I have in mind is the following.  Someone wants to check
> > the feature and simply writes "opportunistic" to /sys/power/policy and "mem" to
> > /sys/power/state without any drivers or apps that use suspend blockers.
> >
> > How in that case is the system supposed to break out of the suspend-resume loop
> > resulting from this?  I don't see right now, because the main blocker is
> > inactive, there are no other blockers that can be activated and it is next to
> > impossible to write to /sys/power/state again.
> 
> I guess we could set a flag when a suspend blocker is registered and
> refuse to enter opportunistic mode if no blockers have ever been
> registered.
> 
> It does seem like extra effort to go through to handle a "don't do
> that" type scenario (entering into opportunistic suspend without
> anything that will prevent it).

I agree, but I think it's necessary.  We shouldn't add interfaces that hurt
users if not used with care.

Thanks,
Rafael