ddi_removing_power(9F)					   Kernel Functions for Drivers 				    ddi_removing_power(9F)

NAME

       ddi_removing_power - check whether DDI_SUSPEND might result in power being removed from a device

SYNOPSIS

       #include <sys/ddi.h>
       #include <sys/sunddi.h>

       int ddi_removing_power(dev_info_t *dip);

INTERFACE LEVEL

       Solaris DDI specific (Solaris DDI)

DESCRIPTION

       The  ddi_removing_power()  function  indicates  whether	a  currently pending call into a driver's detach(9E) entry point with a command of
       DDI_SUSPEND is likely to result in power being removed from the device.

       ddi_removing_power() can return true and power still not be removed from the device due to a failure to suspend and power off the system.

PARAMETERS

       The ddi_removing_power() function supports the following parameter:

       dip    pointer to the device's dev_info structure

RETURN VALUES

       The ddi_removing_power() function returns:

       1    Power might be removed by the framework as a result of the pending DDI_SUSPEND call.

       0    Power will not be removed by the framework as a result of the pending DDI_SUSPEND call.

EXAMPLES

       Example 1 Protecting a Tape from Abrupt Power Removal

       A tape driver that has hardware that would damage the tape if power is removed might include this code in its detach(9E) code:

	 int
	      xxdetach(dev_info_t *dip, ddi_detach_cmd_t cmd)
	      {

	      ...
		   case DDI_SUSPEND:
		   /*
		    * We do not allow DDI_SUSPEND if power will be removed and
		    * we have a device that damages tape when power is removed
		    * We do support DDI_SUSPEND for Device Reconfiguration,
		    * however.
		    */
		      if (ddi_removing_power(dip) && xxdamages_tape(dip))
			 return (DDI_FAILURE);
		   ...

ATTRIBUTES

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

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Interface Stability	     |Committed 		   |
       +-----------------------------+-----------------------------+

SEE ALSO

       attributes(5), cpr(7), attach(9E), detach(9E)

       Writing Device Drivers

SunOS 5.11							   14 March 2001					    ddi_removing_power(9F)