'\" te
.\" Copyright (c) 2002, Sun Microsystems, Inc. All Rights Reserved.
.TH ddi_removing_power 9F "14 March 2001" "SunOS 5.11" "Kernel Functions for Drivers"
.SH NAME
ddi_removing_power \- check whether \fBDDI_SUSPEND\fR might result in power being removed from a device
.SH SYNOPSIS
.LP
.nf
#include <sys/ddi.h>
#include <sys/sunddi.h>

\fBint\fR \fBddi_removing_power\fR(\fBdev_info_t\fR \fI*dip\fR);
.fi

.SH INTERFACE LEVEL
.sp
.LP
Solaris DDI specific (Solaris DDI)
.SH DESCRIPTION
.sp
.LP
The \fBddi_removing_power()\fR function indicates whether a currently pending call into a driver's \fBdetach\fR(9E) entry point with a command of \fBDDI_SUSPEND\fR is likely to result in power being removed from the device.
.sp
.LP
\fBddi_removing_power()\fR can return true and power still not be removed from the device due to a failure to suspend and power off the system.
.SH PARAMETERS
.sp
.LP
The \fBddi_removing_power()\fR function supports the following parameter:
.sp
.ne 2
.mk
.na
\fB\fIdip\fR\fR
.ad
.RS 7n
.rt  
pointer to the device's \fBdev_info\fR structure
.RE

.SH RETURN VALUES
.sp
.LP
The \fBddi_removing_power()\fR function returns:
.sp
.ne 2
.mk
.na
\fB\fB1\fR\fR
.ad
.RS 5n
.rt  
Power might be removed by the framework as a result of the pending \fBDDI_SUSPEND\fR call.
.RE

.sp
.ne 2
.mk
.na
\fB\fB0\fR\fR
.ad
.RS 5n
.rt  
Power will not be removed by the framework as a result of the pending \fBDDI_SUSPEND\fR call.
.RE

.SH EXAMPLES
.LP
\fBExample 1 \fRProtecting a Tape from Abrupt Power Removal
.sp
.LP
A tape driver that has hardware that would damage the tape if power is removed might include this code in its \fBdetach\fR(9E) code:

.sp
.in +2
.nf
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);
          ...
.fi
.in -2

.SH ATTRIBUTES
.sp
.LP
See \fBattributes\fR(5) for descriptions of the following attributes:
.sp

.sp
.TS
tab() box;
cw(2.75i) |cw(2.75i) 
lw(2.75i) |lw(2.75i) 
.
ATTRIBUTE TYPEATTRIBUTE VALUE
_
Interface StabilityCommitted
.TE

.SH SEE ALSO
.sp
.LP
\fBattributes\fR(5), \fBcpr\fR(7), \fBattach\fR(9E), \fBdetach\fR(9E)
.sp
.LP
\fIWriting Device Drivers\fR