Driver Entry Points                                     power(9E)



NAME
     power - power a device attached to the system

SYNOPSIS
     #include 
     #include 



     int prefixpower(devinfot *dip, int component, int level);


INTERFACE LEVEL
     Solaris DI specific (Solaris  DI).  This  entry  point  is
     required.  If  the  driver writer does not supply this entry
     point, the value NUL must be used in the cbops(9S)  struc-
     ture instead.

PARAMETERS
     dip          Pointer to the device's devinfo structure.


     component    Component of the driver to be managed.


     level        Desired component power level.


DESCRIPTION
     The power(9E) function is the device-specific Power  Manage-
     ment  entry  point.  This function is called when the system
     wants the driver to set the  power  level  of  component  to
     level.


     The level argument is  the  driver-defined  power  level  to
     which  the component needs to be set. Except for power level
     0, which is interpreted by the framework  to  mean  "powered
     off,"  the  interpretation  of  level  is entirely up to the
     driver.


     The component argument is the component of the device to  be
     power-managed.  The  interpretation of component is entirely
     up to the driver.


     When a requested power transition would cause the device  to
     lose  state, the driver must save the state of the device in
     memory. When a requested power transition requires state  to
     be restored, the driver must restore that state.




SunOS 5.11          Last change: 12 Dec 2003                    1






Driver Entry Points                                     power(9E)



     If a requested power transition for one  component  requires
     another  component  to  change  power state before it can be
     completed, the driver must call  pmraisepower(9F)  to  get
     the  other  component changed, and the power(9E) entry point
     must support being re-entered.


     If the system requests an inappropriate power transition for
     the  device  (for  example, a request to power down a device
     which has just become busy), then the power level should not
     be changed and power should return DIFAILURE.

RETURN VALUES
     The power() function returns:

     DISUCES    Successfully set the power to  the  requested
                    level.


     DIFAILURE    Failed to set  the  power  to  the  requested
                    level.


CONTEXT
     The power() function is called from user or  kernel  context
     only.

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



     
           ATRIBUTE TYPE               ATRIBUTE VALUE       
    
     Interface stability          Committed                   
    


SEE ALSO
     attach(9E),        detach(9E),        pmbusycomponent(9F),
     pmidlecomponent(9F), pmraisepower(9F), cbops(9S)


     Writing Device Drivers


     Using Power Management






SunOS 5.11          Last change: 12 Dec 2003                    2