• Rafael J. Wysocki's avatar
    PM: Move disabling/enabling runtime PM to late suspend/early resume · 9f6d8f6a
    Rafael J. Wysocki authored
    Currently, the PM core disables runtime PM for all devices right
    after executing subsystem/driver .suspend() callbacks for them
    and re-enables it right before executing subsystem/driver .resume()
    callbacks for them.  This may lead to problems when there are
    two devices such that the .suspend() callback executed for one of
    them depends on runtime PM working for the other.  In that case,
    if runtime PM has already been disabled for the second device,
    the first one's .suspend() won't work correctly (and analogously
    for resume).
    
    To make those issues go away, make the PM core disable runtime PM
    for devices right before executing subsystem/driver .suspend_late()
    callbacks for them and enable runtime PM for them right after
    executing subsystem/driver .resume_early() callbacks for them.  This
    way the potential conflitcs between .suspend_late()/.resume_early()
    and their runtime PM counterparts are still prevented from happening,
    but the subtle ordering issues related to disabling/enabling runtime
    PM for devices during system suspend/resume are much easier to avoid.
    Reported-and-tested-by: default avatarJan-Matthias Braun <jan_braun@gmx.net>
    Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
    Reviewed-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
    Reviewed-by: default avatarKevin Hilman <khilman@deeprootsystems.com>
    Cc: 3.4+ <stable@vger.kernel.org>
    9f6d8f6a
main.c 33.4 KB