Device and Network Interfaces                              cpr(7)

NAME
     cpr - Suspend and resume module

SYNOPSIS
     /platform/'uname -m'/kernel/misc/cpr

DESCRIPTION
     The cpr 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 tran-
     sport.  The cpr module should not be used in place of a nor-
     mal 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 opera-
     tion is conducted.

     dtpower(1M) or  power.conf(4)  are  used  to  configure  the
     suspend-resume  feature.

     The speed of suspend  and resume  operations can range  from
     15  seconds  to  several  minutes,  depending  on the system
     speed, memory size, and load.

     During resume operation, the SIGTHAW 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
     SIGTHAW to restore the state prior to suspend . For example,
     X can refresh the screen in response to SIGTHAW.

     In some cases the  cpr 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   will  fail and an error message will be 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.

     A  suspend  may also fail when devices or processes are per-
     forming critical or time-sensitive operations (such as real-
     time operations). The system will remain in its current run-
     ning 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
     always  succeed,  barring  external  influences  such  as  a
     hardware reconfiguration.

SunOS 5.8           Last change: 15 Oct 1999                    1

Device and Network Interfaces                              cpr(7)

     Some network-based applications may fail across  a   suspend
     and resume
      cycle.  This largely depends on the underlying network pro-
     tocol  and  the applications involved.  In general, applica-
     tions that retry and automatically  reestablish  connections
     will  continue to operate  transparently on a resume  opera-
     tion; those applications that do not will likely fail.

ATTRIBUTES
     See attributes(5) for descriptions of the  following  attri-
     butes:

     ____________________________________________________________
    |       ATTRIBUTE TYPE        |       ATTRIBUTE VALUE       |
    |_____________________________|_____________________________|
    | Availability                | SUNWcpr                     |
    |_____________________________|_____________________________|
    | Interface stability         | Unstable                    |
    |_____________________________|_____________________________|

SEE ALSO
     dtpower(1M) (OpenWindows  Reference  Manual),  pmconfig(1M),
     uadmin(1M), uadmin(2), power.conf(4), attributes(5)

     Using Power Management

     Writing Device Drivers

NOTES
     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.

     Suspend-resume is currently  supported only on a limited set
     of  hardware  platforms.  Please  see   the book Using Power
     Management for a complete list  of  platforms  that  support
     system  Power  Management.  See  uname(2) to programatically
     determine if the machine supports suspend-resume.

BUGS
     In extremely rare occasions, the system may fail during  the
     early stages of a resume operation.  In this small window it
     is theoretically
      possible to be stuck in a loop such that  the  system  does
     not resume and does not boot normally.  If you are in such a
     loop, get to the PROM ok prompt using the  <L1+A>  keys  and
     enter the following command:

SunOS 5.8           Last change: 15 Oct 1999                    2

Device and Network Interfaces                              cpr(7)

     <ok> set-default boot-file

     This command resets the system and with  the  next  power-on
     the system
      will boot normally.

SunOS 5.8           Last change: 15 Oct 1999                    3