DDI_REMOVING_POWER(9F)DDI_REMOVING_POWER(9F)NAMEddi_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_SUS‐
PEND 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 ALSOattributes(5), cpr(7), attach(9E), detach(9E)
Writing Device Drivers
Mar 14, 2001 DDI_REMOVING_POWER(9F)