pm(9P)							   Kernel Properties for Drivers						    pm(9P)

NAME

       pm - Power Management properties

DESCRIPTION

       The  pm-hardware-state  property  can be used to influence the behavior of the Power Management framework. Its syntax and interpretation is
       described below.

       Note that this property is only interpreted by the system immediately after the device has successfully attached. Changes in  the  property
       made by the driver after the driver has attached will not be recognized.

       pm-hardware-state  is  a string-valued property. The existence of the pm-hardware-state property indicates that a device needs special han-
       dling by the Power Management framework with regard to its hardware state.

       If the value of this property is needs-suspend-resume, the device has a hardware state that cannot be deduced by the framework. The  frame-
       work  definition  of a device with hardware state is one with a reg property. Some drivers, such as SCSI disk and tape drivers, have no reg
       property but manage devices with "remote" hardware. Such a device must have a pm-hardware-state property with  a  value	of  needs-suspend-
       resume for the system to identify it as needing a call to its detach(9E) entry point with command DDI_SUSPEND when system is suspended, and
       a call to attach(9E) with command DDI_RESUME when system is resumed. For devices using original Power Management interfaces (which are  now
       obsolete)  detach(9E)  is  also	called	with  DDI_PM_SUSPEND  before  power  is  removed  from	the  device, and attach(9E) is called with
       DDI_PM_RESUME after power is restored.

       A value of no-suspend-resume indicates that, in spite of the existence of a reg property, a device has no hardware state that needs  saving
       and  restoring. A device exporting this property will not have its detach() entry point called with command DDI_SUSPEND when system is sus-
       pended, nor will its attach() entry point be called with command DDI_RESUME when system is resumed. For devices using the original (and now
       obsolete)  Power  Management interfaces, detach(9E) will not be called with DDI_PM_SUSPEND command before power is removed from the device,
       nor attach(9E) will be called with DDI_PM_RESUME command after power is restored to the device.

       A value of parental-suspend-resume indicates that the device does not implement the detach(9E)  DDI_SUSPEND  semantics,	nor  the  attach()
       DDI_RESUME  semantics, but that a call should be made up the device tree by the framework to effect the saving and/or restoring of hardware
       state for this device. For devices using original Power Management interfaces (which are now obsolete), it also indicates that  the  device
       does  not  implement the detach(9E) DDI_PM_SUSPEND semantics, nor the attach(9E) DDI_PM_RESUME semantics, but that a call should be made up
       the device tree by the framework to effect the saving and/or restoring the hardware state for this device.

ATTRIBUTES

       See attributes(5) for descriptions of the following attributes:

       +--------------------------+--------------------------------+
       |     ATTRIBUTE TYPE	  |	   ATTRIBUTE VALUE	   |
       +--------------------------+--------------------------------+
       |Interface stability	  |Evolving			   |
       +--------------------------+--------------------------------+

SEE ALSO

       power.conf(4), pm(7D), attach(9E), detach(9E), pm_busy_component(9F), pm_idle_component(9F), pm-components(9P)

       Writing Device Drivers

SunOS 5.10							    20 Jan 2004 							    pm(9P)