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solaris:ddi_removing_power.9f

ddi_removing_power


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(7) for descriptions of the following attributes:

SEE ALSO

cpr(4), attributes(7), attach(9E), detach(9E)

Writing Device Drivers


solaris/ddi_removing_power.9f.txt · Last modified: 2023/07/19 08:58 by A User Not Logged in