'\" te
.\"  Copyright (c) 2001, Sun Microsystems, Inc.
.\"  All Rights Reserved
.\" The contents of this file are subject to the terms of the Common Development and Distribution License (the "License").  You may not use this file except in compliance with the License.
.\" You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE or http://www.opensolaris.org/os/licensing.  See the License for the specific language governing permissions and limitations under the License.
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.TH CPR 7 "May 7, 2001"
.SH NAME
cpr \- Suspend and resume module
.SH SYNOPSIS
.LP
.nf
\fB/platform/'uname -m'/kernel/misc/cpr\fR
.fi

.SH DESCRIPTION
.sp
.LP
The \fBcpr\fR module is a loadable module used to suspend and resume the entire
system. You may wish to suspend a system to save power or to power off
temporarily for transport. The \fBcpr\fR module should not be used in place of
a normal shutdown when performing any hardware reconfiguration or replacement.
In order for the resume operation to succeed, it is important that the hardware
configuration remain the same. When the system is suspended, the entire system
state is preserved in non-volatile storage until a resume operation is
conducted.
.sp
.LP
\fBdtpower\fR(1M) or \fBpower.conf\fR(4) are used to configure the
suspend-resume feature.
.sp
.LP
The speed of suspend  and resume operations can range from 15 seconds to
several minutes, depending on the system speed, memory size, and load.
.sp
.LP
During resume operation, the \fBSIGTHAW\fR signal is sent to all processes to
allow them to do any special processing in response to suspend-resume
operation. Normally applications are not required to do any special processing
because of suspend-resume, but some specialized processes can use
\fBSIGTHAW\fR to restore the state prior to suspend. For example, \fBX\fR can
refresh the screen in response to \fBSIGTHAW\fR.
.sp
.LP
In some cases the \fBcpr\fR module may be unable to perform the suspend
operation. If a system contains additional devices outside the standard shipped
configuration, it is possible that device drivers for these additional devices
might not support suspend-resume  operations. In this case, the suspend fails
and an error message is displayed. These devices must be removed or their
device drivers unloaded for the  suspend operation to succeed. Contact the
device manufacturer to obtain a new version of device driver that supports
suspend-resume.
.sp
.LP
A  suspend  may also fail when devices or processes are performing critical or
time-sensitive operations (such as realtime operations). The system will remain
in its current running state. Messages reporting the failure will be displayed
on the console and status returned to the caller. Once the system is
successfully suspended the resume operation will succeed, barring external
influences such as a hardware reconfiguration.
.sp
.LP
Some network-based applications may fail across a suspend and resume cycle.
This largely depends on the underlying network protocol and the applications
involved.  In general, applications that retry and automatically reestablish
connections will continue to operate  transparently on a resume  operation;
those applications that do not will likely fail.
.SH ATTRIBUTES
.sp
.LP
See \fBattributes\fR(5) for descriptions of the following attributes:
.sp

.sp
.TS
box;
c | c
l | l .
ATTRIBUTE TYPE	ATTRIBUTE VALUE
_
Interface stability 	Unstable
.TE

.SH SEE ALSO
.sp
.LP
\fBdtpower\fR(1M) (OpenWindows Reference Manual), \fBpmconfig\fR(1M),
\fBuadmin\fR(1M), \fBuadmin\fR(2), \fBpower.conf\fR(4), \fBattributes\fR(5)
.sp
.LP
\fIUsing Power Management\fR
.sp
.LP
\fIWriting Device Drivers\fR
.SH NOTES
.sp
.LP
Certain device operations such as tape and floppy disk activities are not
resumable due to the nature of removable media.  These activities are detected
at suspend time, and must be stopped before the suspend  operation will
complete successfully.
.sp
.LP
Suspend-resume is currently  supported only on a limited set of hardware
platforms. Please see  the book \fIUsing Power Management\fR for a complete
list of platforms that support system Power Management. See \fBuname\fR(2) to
programatically determine if the machine supports suspend-resume.