xref: /illumos-gate/usr/src/man/man9f/ddi_removing_power.9f (revision dd72704bd9e794056c558153663c739e2012d721)
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DDI_REMOVING_POWER 9F "Mar 14, 2001"
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: 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(7) for descriptions of the following attributes:
ATTRIBUTE TYPE ATTRIBUTE VALUE
Interface Stability Committed
SEE ALSO
cpr (4), attributes (7), attach (9E), detach (9E)

Writing Device Drivers