• Rafael J. Wysocki's avatar
    ACPI / PM: Rework the handling of devices depending on power resources · bc9b6407
    Rafael J. Wysocki authored
    Commit 0090def6 (ACPI: Add interface to register/unregister device
    to/from power resources) made it possible to indicate to the ACPI
    core that if the given device depends on any power resources, then
    it should be resumed as soon as all of the power resources required
    by it to transition to the D0 power state have been turned on.
    
    Unfortunately, however, this was a mistake, because all devices
    depending on power resources should be treated this way (i.e. they
    should be resumed when all power resources required by their D0
    state have been turned on) and for the majority of those devices
    the ACPI core can figure out by itself which (physical) devices
    depend on what power resources.
    
    For this reason, replace the code added by commit 0090def6 with a
    new, much more straightforward, mechanism that will be used
    internally by the ACPI core and remove all references to that code
    from kernel subsystems using ACPI.
    
    For the cases when there are (physical) devices that should be
    resumed whenever a not directly related ACPI device node goes into
    D0 as a result of power resources configuration changes, like in
    the SATA case, add two new routines, acpi_dev_pm_add_dependent()
    and acpi_dev_pm_remove_dependent(), allowing subsystems to manage
    such dependencies.  Convert the SATA subsystem to use the new
    functions accordingly.
    Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
    bc9b6407
pci-acpi.c 10.3 KB