1.\" Copyright (c) 2001, Sun Microsystems, Inc. 2.\" All Rights Reserved 3.\" 4.\" Copyright 2020 Joyent, Inc. 5.\" 6.\" The contents of this file are subject to the terms of the 7.\" Common Development and Distribution License (the "License"). 8.\" You may not use this file except in compliance with the License. 9.\" 10.\" You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 11.\" or http://www.opensolaris.org/os/licensing. 12.\" See the License for the specific language governing permissions 13.\" and limitations under the License. 14.\" 15.\" When distributing Covered Code, include this CDDL HEADER in each 16.\" file and include the License file at usr/src/OPENSOLARIS.LICENSE. 17.\" If applicable, add the following below this CDDL HEADER, with the 18.\" fields enclosed by brackets "[]" replaced with your own identifying 19.\" information: Portions Copyright [yyyy] [name of copyright owner] 20.\" 21.Dd January 12, 2020 22.Dt CPR 4 23.Os 24.Sh NAME 25.Nm cpr 26.Nd Suspend and resume module 27.Sh SYNOPSIS 28.Pa /platform/i86pc/kernel/misc/amd64/cpr 29.Pa /platform/sun4u/kernel/misc/sparcv9/cpr 30.Sh DESCRIPTION 31The 32.Nm 33module is a loadable module used to suspend and resume the entire system. 34You may wish to suspend a system to save power or to power off 35temporarily for transport. 36The 37.Nm 38module should not be used in place of 39a normal shutdown when performing any hardware reconfiguration or replacement. 40In order for the resume operation to succeed, it is important that the hardware 41configuration remain the same. 42When the system is suspended, the entire system 43state is preserved in non-volatile storage until a resume operation is 44conducted. 45.Pp 46.Xr pmconfig 8 47and 48.Xr power.conf 5 49are used to configure the suspend-resume feature. 50.Pp 51The speed of suspend and resume operations can range from 15 seconds to 52several minutes, depending on the system speed, memory size, and load. 53.Pp 54During resume operation, the 55.Dv SIGTHAW 56signal is sent to all processes to 57allow them to do any special processing in response to suspend-resume 58operation. 59Normally applications are not required to do any special processing 60because of suspend-resume, but some specialized processes can use 61.Dv SIGTHAW 62to restore the state prior to suspend. 63For example, 64.Sy X 65can refresh the screen in response to 66.Dv SIGTHAW . 67.Pp 68In some cases the 69.Nm 70module may be unable to perform the suspend operation. 71If a system contains additional devices outside the standard shipped 72configuration, it is possible that device drivers for these additional devices 73might not support suspend-resume operations. 74In this case, the suspend fails and an error message is displayed. 75These devices must be removed or their 76device drivers unloaded for the suspend operation to succeed. 77Contact the 78device manufacturer to obtain a new version of device driver that supports 79suspend-resume. 80.Pp 81A suspend may also fail when devices or processes are performing critical or 82time-sensitive operations (such as realtime operations). 83The system will remain in its current running state. 84Messages reporting the failure will be displayed 85on the console and status returned to the caller. 86Once the system is 87successfully suspended the resume operation will succeed, barring external 88influences such as a hardware reconfiguration. 89.Pp 90Some network-based applications may fail across a suspend and resume cycle. 91This largely depends on the underlying network protocol and the applications 92involved. 93In general, applications that retry and automatically reestablish 94connections will continue to operate transparently on a resume operation; 95those applications that do not will likely fail. 96.Sh INTERFACE STABILITY 97Unstable 98.Sh SEE ALSO 99.Xr uadmin 2 , 100.Xr power.conf 5 , 101.Xr attributes 7 , 102.Xr pmconfig 8 , 103.Xr uadmin 8 104.Pp 105.%T Writing Device Drivers 106.Sh NOTES 107Certain device operations such as tape and floppy disk activities are not 108resumable due to the nature of removable media. 109These activities are detected 110at suspend time, and must be stopped before the suspend operation will 111complete successfully. 112.Pp 113Suspend-resume is currently supported only on a limited set of hardware 114platforms. 115