Re: removing refrigerator does not help with s2ram vs. fuse deadlocks (was Re: [linux-pm] Re: [PATCH] Remove process freezer from suspend to RAM pathway)

Pavel Machek
2007-07-07T11:56:37Z

Hi!

> > > And also "Userland should not depend on userland services", which is
> > > rather more of a problem.
> >
> > I think you're oversimplifying it, as far as FUSE is concerned.
> >
> > Namely, if there are two userland tasks, A and B, and B is uninterruptible,
> > because A is blocked, then this is not a usual situation.
>
> Fuse is one case of it occuring, and if we end up with more userspace
> drivers then the problem is only going to get worse.

We'll have to solve them as they come.

Face it, hardware drivers _have_ to know about suspend/resume. Even
userspace drivers will have to know about suspend/resume, because they
need to reinit the hw during resume.

Now... most parts of kernel need to know (a bit) about suspend/resume
-- at least enough to play nicely with refrigerator. In retrospect it
is pretty obvious that this covers fused, too, unfortunately noone
noticed that when fuse was designed.

Can we try to solve the suspend vs. fuse problem now? "Just removing
the refrigerator" is not the answer. First, refrigerator is impossible
to remove in few months timeframe, and second, it does not solve the
problem anyway.

(Actually, there are two separate problems with suspend vs. fuse.)
Pavel
--
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