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 handling 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  framework  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 com-
     mand 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 suspended, 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 sav-
     ing 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 dev-
     ice.

ATTRIBUTES

     See attributes(5) for descriptions of the  following  attri-
     butes:

     ____________________________________________________________
    |      ATTRIBUTE TYPE      |         ATTRIBUTE VALUE        |
    |__________________________|________________________________|
    | Interface stability      | Evolving                       |
    |__________________________|________________________________|

SEE ALSO

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

     Writing Device Drivers