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    SubjectRe: [RFD] Automatic suspend
    On Sunday 01 March 2009, Arve Hjønnevåg wrote:
    > On Sat, Feb 28, 2009 at 2:53 PM, Rafael J. Wysocki <> wrote:
    > > On Saturday 28 February 2009, Arve Hjønnevåg wrote:
    > >> Can you summarize what the problems with my current api are? I get the
    > >> impression that you think the overhead of using a list is too high,
    > >> and that timeout support should be removed because you think all
    > >> drivers that use it are broken.
    > >
    > > In no particular order:
    > > 1. One user space process can create an unlimited number of wakelocks. This
    > > shouldn't be possible. Moreover, it is not even necessary for any process
    > > to have more than one wakelock held at any time.
    > This has been addressed. A user space process cannot create more
    > wakelocks than it has filedescriptors.
    > > 2. Timeouts are wrong, because they don't really _solve_ any problem. They are
    > > useful for working around the fact that you can't or you don't want to
    > > modify every piece of code that in principle should take a wakelock and
    > > that's it.
    > Yes, timeouts are sometimes wrong, but they are not always wrong. I
    > gave two examples where the use of timeouts was not incorrect.

    There still is a problem that the same operation can take time X on one
    platform and time Y on another, so how are you going to determine the timeouts
    that will be suitable for all platforms?

    > > However, entire concept of having one code path acting on
    > > behalf of another one on a hunch that it might be doing something making
    > > suspend undesirable is conceptually broken IMO.
    > OK. Do you have an alternative?

    Well, IMO every code path doing something that makes automatic suspend
    undesirable should use a suspend blocker of some sort. I'm afraid any other
    approach will be unreliable and racy.

    > I my opinion this is how the entire system works if you do autosuspend
    > without a mechanism like wakelocks.

    It surely hasn't been designed with automatic suspend in mind.

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