• Rafael J. Wysocki's avatar
    ACPI: power: Rework turning off unused power resources · 6381195a
    Rafael J. Wysocki authored
    Make turning off unused power resources (after the enumeration of
    devices and during system-wide resume from S3) more straightforward
    by using the observation that the power resource state stored in
    struct acpi_power_resource can be used to determine whether or not
    the give power resource has any users.
    
    Namely, when the state of the power resource is unknown, its _STA
    method has never been evaluated (or the evaluation of it has failed)
    and its _ON and _OFF methods have never been executed (or they have
    failed to execute), so for all practical purposes it can be assumed
    to have no users (or to be unusable).  Therefore, instead of checking
    the number of power resource users, it is sufficient to check if its
    state is known.
    
    Moreover, if the last known state of a given power resource is "off",
    it is not necessary to turn it off, because it has been used to
    initialize the power state or the wakeup power resources list of at
    least one device and either its _STA method has returned 0 ("off"),
    or its _OFF method has been successfully executed already.
    
    Accordingly, modify acpi_turn_off_unused_power_resources() to do the
    above checks (which are suitable for both uses of it) instead of
    using the number of power resource users or evaluating its _STA
    method, drop its argument (which is not useful any more) and update
    its callers.
    
    Also drop the users field from struct acpi_power_resource as it is
    not useful any more.
    Tested-by: default avatarDave Olsthoorn <dave@bewaar.me>
    Tested-by: default avatarShujun Wang <wsj20369@163.com>
    Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
    6381195a
scan.c 61.2 KB