Re: Q: Clarification about extra option ..Re: Re: [PATCH] pvops: Make suspend work when CONFIG_SUSPEND=n

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

On Friday, March 04, 2011, Konrad Rzeszutek Wilk wrote:
> .. snip..
> > >>  Someone suggested creating a new user visible hibernate symbol that would
> > >> solve this issue and make the main hibernate logic depend on this symbol rather
> > >> than the HIBERNATE symbol. I could certainly spin up a patch for that but nobody
> > >> seemed to have reached a conclusion.
> > >
> > > Please do. I was under the understanding that we were waiting for a victi^H^H^Hvolunteer
> > > to implement that.
> > >
> > > That was the only thing gatting your patchset going in.
> > >
> > >
> > 
> > I certainly would have long time ago but for this comment in the thread
> > "xen: fix XEN_SAVE_RESTORE Kconfig dependencies"
> > 
> > Rafael:
> >  I think we can introduce CONFIG_HIBERNATE_INTERFACE that will be user-visible
> > option instead of CONFIG_HIBERNATION and will select the latter.  Then,
> > CONFIG_XEN_SAVE_RESTORE will also be able to select CONFIG_HIBERNATION without
> > building the hibernate interface in, which will prevent user space from being
> > confused, but that will cause too much code to be built anyway.
> > 
> > If by "too much code to be built", he meant the increase in kernel
> > image size, then its not much of a deal :P.
> > But if he meant, "too much code rework", then it is an issue.
> 
> The idea here is that the /sys/power/state won't be exposed with the "disk"
> option.
> 
> > 
> > But IMO, the CONFIG_HIBERNATE_INTERFACE needs to go in,
> > only in the main hibernation initiator logic, as we still need the
> > CONFIG_HIBERNATE
> > pieces of every driver anyway (their freeze/thaw routines).
> 
> Right. The idea here is to seperate the sysfs interface to be behind
> another config option. So you can still enable the hibernate kernel code
> but without exposing it to the userland.
> 
> Rafael,
> 
> That is the general idea, right?

Right.  We can only make the code in kernel/power/snapshot.c depend on
CONFIG_HIBERNATE_INTERFACE and the ioctl interface too.

Thanks,
Rafael