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

illumos DDI specific (illumos 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:

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

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(7) for descriptions of the following attributes:

ATTRIBUTE TYPE	ATTRIBUTE VALUE
Interface Stability	Committed