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    SubjectRe: [PATCH v4 0/5] Functional dependencies between devices
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    Hi Rafael,

    On 2016-09-29 02:24, Rafael J. Wysocki wrote:
    > Hi Everyone,
    >
    > On Thursday, September 08, 2016 11:25:44 PM Rafael J. Wysocki wrote:
    >>> Hi Everyone,
    >>>
    >>> This is a refresh of the functional dependencies series that I posted last
    >>> year and which has picked up by Marek quite recently. For reference,
    >>> appended is my introductory message sent previously (which may be
    >>> slightly outdated now).
    >>>
    >>> As last time, the first patch rearranges the code around
    >>> __device_release_driver() a bit to prepare it for the next one (it
    >>> actually hasn't changed AFAICS).
    >>>
    >>> The second patch introduces the actual device links mechanics, but without
    >>> system suspend/resume and runtime PM support which are added by the
    >>> subsequent patches.
    >>>
    >>> Some bugs found by Marek during his work on these patches should be fixed
    >>> here. In particular, the endless recursion in device_reorder_to_tail()
    >>> which simply was broken before.
    >>>
    >>> There are two additional patches to address the issue with runtime PM
    >>> support
    >>> that occured when runtime PM was disabled for some suppliers due to a PM
    >>> sleep transition in progress. Those patches simply make runtime PM
    >>> helpers
    >>> return 0 in that case which may be controversial, so please let me know if
    >>> there are concerns about those.
    >>>
    >>> The way device_link_add() works is a bit different, as it takes an
    >>> additional
    >>> status argument now. That makes it possible to create a link in any
    >>> state,
    >>> with extra care of course, and should address the problem pointed to by
    >>> Lukas
    >>> during the previous discussion.
    >>>
    >>> Also some comments from Tomeu have been addressed.
    >> An update here.
    >>
    >> The first patch hasn't changed, so I'm resending it.
    >>
    >> The majority of changes in the other patches are in order to address Lukas'
    >> comments.
    >>
    >> First off, I added a DEVICE_LINK_STATELESS flag that will prevent the driver
    >> core from trying to maintain device links having it set.
    >>
    >> Also, the DEVICE_LINK_PERSISTENT flag was dropped (as link "persistence" is
    >> the default behavior now) and there's a new one, DEVICE_LINK_AUTOREMOVE,
    >> that will cause the driver core to remove the link on the consumer driver
    >> unbind.
    >>
    >> Moreover, the code checks attempts to create a link between a parent and a
    >> child device now and actively prevents that from happening.
    >>
    >> The changelog of the second patch has been updated as requested by Ulf.
    >>
    >> The third patch was updated to fix a bug related to the (previously missing)
    >> clearing of power.direct_complete for supplier devices having consumers that
    >> don't use direct_complete.
    >>
    >> The next two (runtime PM) patches turned out to be unnecessary, so I've
    >> dropped them.
    >>
    >> The runtime PM patch [4/5] was reorganized somewhat to reduce the
    >> indentation
    >> level in there, but the code flow introduced by it is essentially the same
    >> and the last patch was simply rebased on top of the new series.
    > Time for another update. :-)
    >
    > Fewer changes this time, mostly to address issues found by Lukas and Marek.
    >
    > The most significant one is to make device_link_add() cope with the case when
    > the consumer device has not been registered yet when it is called. The
    > supplier device still is required to be registered and the function will return
    > NULL if that is not the case.
    >
    > Another significant change is in patch [4/5] that now makes the core apply
    > pm_runtime_get_sync()/pm_runtime_put() to supplier devices around the probing
    > of a consumer one (in analogy with the parent).

    Thanks for the update! Updated version fixes all the remaining issues.

    Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>

    Best regards
    --
    Marek Szyprowski, PhD
    Samsung R&D Institute Poland

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