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

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

On Saturday 15 May 2010, Arve Hjønnevåg wrote:
> On Fri, May 14, 2010 at 3:32 PM, Kevin Hilman
> <khilman@deeprootsystems.com> wrote:
> > Matthew Garrett <mjg@redhat.com> writes:
> >
> >> On Fri, May 14, 2010 at 02:20:43PM -0600, Paul Walmsley wrote:
> >>> Hello,
> >>>
> >>> On Mon, 3 May 2010, Matthew Garrett wrote:
> >>>
> >>> > I agree that the runtime scenario is a far more appealing one from an
> >>> > aesthetic standpoint, but so far we don't have a very compelling
> >>> > argument for dealing with the starting and stopping of userspace.
> >>>
> >>> The problem of how to start and stop (some) userspace is not specifically
> >>> system power management-related, nor top-down, /sys/power/state-suspend
> >>> related.  PM is just one potential user.
> >>>
> >>> It's hard to see how the Android opportunistic suspend approach would be
> >>> useful for the other use-cases (e.g., checkpoint/restart).  On the other
> >>> hand, it's easier to see how something like freezer cgroups could be
> >>> useful for system power management and checkpoint/restart.
> >>
> >> And difficult to see how to implement something using freezer cgroups
> >> that actually works in this case. Look, I don't want to sound like I
> >> have a one-track mind or anything, but all of these arguments would be
> >> significantly more compelling if someone would actually provide a
> >> concrete implementation proposal that deals with the set of use-cases
> >> that Google's implementation does and which doesn't make anyone cry.
> >
> > That might be possible if this "set of use-cases" was available
> > someplace.  At least I haven't seen it, and would expect it to be in
> > the docs included with patch 1.
> >
> > Another likely reason that that there hasn't been an alternate
> > proposal (at least from some of us that are raising concerns) is
> > because we already have a working solution to dynamic, system-wide PM
> > that is 1) already in mainline and 2) shipping on consumer devices
> > with very strict power budgets (as already pointed out in detail by
> > Paul[2].)
> >
> > Yes, "excruciatingly bad" apps can kill PM on these systems since
> > anyone can write apps, but the same is true on an opporunistic-suspend
> > based system since any app could hold a suspend blocker whenever it
> > wants.
> >
> 
> No, apps need permission to block suspend.

Are you referring to the fact the permissions of the special device file or
something different?

Rafael