Kernel Functions for Drivers                   pmtranscheck(9F)



NAME
     pmtranscheck - Device power cycle advisory check

SYNOPSIS
     #include 

     int pmtranscheck(struct pmtransdata *datap, timet *intervalp);


INTERFACE LEVEL
     Solaris DI specific (Solaris DI)

PARAMETERS
     datap    Pointer to a pmtransdata structure


     intervalp    Pointer to  time  difference  when  next  power
                  cycle will be advised


DESCRIPTION
     The pmtranscheck() function checks  if  a  power-cycle  is
     currently advised based on data in the pmtransdata  struc-
     ture. This function is provided to prevent damage to devices
     from  excess power cycles; drivers for devices that are sen-
     sitive  to  the  number  of   power   cycles   should   call
     pmtranscheck()   from   their  power(9E)  function  before
     powering-off a device. If  pmtranscheck()  indicates  that
     the device should not be power cycled, the driver should not
     attempt to power cycle the device and should fail  the  call
     to power(9E) entry point.


     If pmtranscheck() returns that it is not advised to  power
     cycle  the  device,  it attempts to calculate when the  next
     power cycle is advised, based on the supplied parameters. In
     such   case,  intervalp  returns  the  time  difference  (in
     seconds) from the current time to when the next power  cycle
     is  advised.  If the time for the next power cycle cannot be
     determined, intervalp indicates 0.


     To avoid excessive calls to the power(9E) entry point during
     a  period  when  power  cycling  is  not advised, the driver
     should mark the corresponding device component busy for  the
     intervalp  time period (if interval is not 0). Conveniently,
     the  driver   can   utilize   the   fact   that   calls   to
     pmbusycomponent(9F)  are  stacked. If power cycling is not
     advised, the  driver  can  call  pmbusycomponent(9F)   and
     issue  a  timeout(9F)  for the intervalp time. The timeout()
     handler can issue  the  corresponding  pmidlecomponent(9F)
     call.



SunOS 5.11          Last change: 16 Oct 1999                    1






Kernel Functions for Drivers                   pmtranscheck(9F)



     When  the  format  field  of   pmtransdata   is   set   to
     DCSCSIFORMAT,  the  caller  must   provide  valid  data in
     svcdate[], lifemax, and ncycles. Currently,  flag  must  be
     set to 0.

       struct pmscsicycles {
                 int lifemax;                     /* lifetime max power cycles */
                 int ncycles;                     /* number of cycles so far */
                 char svcdate[DCSCSIMFRLEN];  /* service date YW */
                 int flag;                        /* reserved for future */
            };

            struct pmtransdata {
                 int format;                      /* data format */
                 union {
                      struct pmscsicycles scsicycles;
                 } un;
            };


RETURN VALUES
     1     Power cycle is advised


     0     Power cycle is not advised


     -1    Error due to invalid argument.


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



     
           ATRIBUTE TYPE               ATRIBUTE VALUE       
    
     Interface Stability          Committed                   
    


SEE ALSO
     power.conf(4), attributes(5), power(9E)


     Writing Device Drivers


     Using Power Management




SunOS 5.11          Last change: 16 Oct 1999                    2