slackware-current/source/ap/pm-utils

README.SLACKWARE
20130512 - rworkman@slackware.com

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PLEASE READ THIS ENTIRE FILE BEFORE REPORTING PROBLEMS OR ASKING FOR HELP!
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One of these routines should tell you whether any of the operations
are supported by your current kernel/userspace at all:

  for i in hibernate suspend suspend-hybrid ; do
    pm-is-supported --$i \
      && echo "$i is supported" \
      || echo "$i is not supported" ;
  done

  *OR*

  cat /sys/power/state

Assuming they are supported, running "pm-suspend" as root should do a suspend
to ram, and "pm-hibernate" should suspend to disk. Note that you must have a 
swap partition (or file, but partition is easier) which is large enough 
(2x ram is good here) and the relevant initrd lines and such for this to work. 
If you're not familiar with all of that, don't test pm-hibernate.
I don't have hardware which supports suspend-hybrid, so I have no idea if/how
it works at all.

Here's the short version of using suspend to disk:

Stanza in /etc/lilo.conf should look something like this:
  image = /boot/vmlinuz-generic-smp-3.8.13-smp
    initrd = /boot/initrd.gz
    append = "resume=/dev/sda2"
    root = /dev/sda1
    label = genericsmp.s
    read-only

/etc/mkinitrd.conf should look something like this:
  MODULE_LIST="ext4"
  ROOTDEV="/dev/sda1"
  ROOTFS="ext4"
  RESUMEDEV="/dev/sda2"

mkinitrd command invocation would be this:
  mkinitrd -c -k 3.8.13-smp -F

All of the above assumes at least a cursory understanding of what those
commands and parameters do. If it's not clear, don't attempt it on a
system that you can't easily reinstall without concern.

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Once you confirm that a suspend and resume cycle works as expected, you might
automate the process with some acpi magic, but a better option is to use the 
power manager daemon included with your choice of desktop environment (both 
kde and xfce have one).

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/* TODO: these links are now dead.  That's mostly okay, because the vast 
   majority of the hardware out there these days doesn't require any quirks
   at all any more.  Hopefully you won't be in the minority :-)
   Addendum: it's now been about three years since the above text was
   written, and I've had zero reports of hardware requiring additional
   quirks.  Just FYI.  :-)
*/

If it doesn't work by default for you, consider having a look at
  http://people.freedesktop.org/~hughsient/quirk/quirk-suspend-index.html
for some debugging hints.  Pay particular attention to this page:
  http://people.freedesktop.org/~hughsient/quirk/quirk-suspend-try.html

If you are able to get your machine to suspend/resume correctly by passing
additional quirks on the command line, then I would like to know about it so
that upstream hal-info can get the correct information to use.  Please email
the make/model and other relevant information about your machine along with
the full output of "lshal" and "lspci" attached, and what extra quirks you
needed to add for successful suspend/resume to rworkman@slackware.com

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If you need the system to do certain operations before going to sleep and
then undo them (or perhaps do something new) when waking back up, pm-utils
supports something called "hooks."  The hooks installed by packages (not only
pm-utils itself) should be in /usr/lib(64)/pm-utils/sleep.d/, while any hooks 
installed by the local system administrator (e.g. things that are only an
issue on that one machine) should be in /etc/pm/sleep.d/.

Looking at some of the existing hooks should give you a decent idea of their
capabilities; as a head start, the functions used in the hooks are declared 
in /usr/lib(64)/pm-utils/functions, which is inherited elsewhere by 
/usr/lib(64)/pm-utils/pm-functions.  Note that an error exit code on any hook
will cause the sleep operation to fail, so if you don't care whether your
hook executes successfully, be sure to return an exit code of 0 (success) if
you don't want the suspend operation to fail.  Some other exit codes are 
also available; none of these will cause the suspend to fail:
  $NA (not applicable), $NX (hook not executable), and $DX (hook disabled)

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The default powersave hooks are in /usr/lib(64)/pm-utils/power.d/ -- if you
need to override any parameters set in those, you can do so with same-named
files in /etc/pm/power.d/  As an example, if you wanted to change the hdparm 
setting for your hard drive's power management setting, you would copy the 
entire file at /usr/lib(64)/pm-utils/power.d/harddrive to /etc/pm/power.d/ 
and edit the copy to reflect your needs, e.g.:

  DRIVE_POWER_MGMT_BAT=128	# edit value as desired
  DRIVE_POWER_MGMT_AC=128	# edit value as desired

Also note that any files in the /etc/pm/ hierarchy must be executable (use 
chmod +x) in order to be used by pm-utils; otherwise, they will be ignored.

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KNOWN ISSUES

****  If you encounter either of these, mail rworkman@slackware.com ****

If your alsa drivers don't correctly save and restore state across a sleep /
resume cycle (due to a buggy driver), then you will need to add the drivers
to a custom file named /etc/pm/config.d/defaults (create the file if it does
not exist already) in a variable named "SUSPEND_MODULES" - see the file at
/usr/lib(64)/pm-utils/defaults for proper format.

The /usr/lib(64)/pm-utils/sleep.d/90clock does not run by default.  It added
over a second to suspend, and the vast majority of hardware does not need it 
to keep the clocks in sync.  If you need this hook, you can set the 
NEED_CLOCK_SYNC environment variable in a custom /etc/pm/config.d/defaults 
file. 

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