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RedHat 9 (Linux i386) - man page for apmd (redhat section 8)

APMD(8) 			    Linux Programmer's Manual				  APMD(8)

NAME
       apmd - Advanced Power Management (APM) daemon

SYNOPSIS
       apmd  [ -c check_seconds ] [ -P proxy_cmd ] [ -p percent_to_log ] [ -qVvW ] [ -w warn_per-
       cent ] [ -? ] [deprecated options]

DESCRIPTION
       apmd is an APM monitoring daemon, and works in conjunction with the APM BIOS driver in the
       OS  kernel.   It  can  execute a command (normally a shell script) when certain events are
       reported by the driver, and will log, via syslogd(8), certain changes in system power sta-
       tus.   When  the  available  battery power becomes very low, it can alert all users on the
       system using several methods.

       When the kernel APM driver notifies the daemon of a pending suspend  or	standby  request,
       apmd  will  invoke  the approprate command, log the event, sync(2) data to the disk, sleep
       briefly to help ensure all the data actually gets to the  disk,	and  then  tell  the  APM
       driver  to  continue its operation.  However, for "critical" suspends (indicating an emer-
       gency shutdown) only the last step (telling the driver to continue) is performed.

       Most uses of this daemon will use the proxy command to support power conservation  activi-
       ties.   This  command  is  either specified using the -P option, or /etc/apm/apmd_proxy by
       default.  It is invoked with one or two arguments:

       start  Invoked when the daemon starts.  Normally sets system-wide power	policy,  such  as
	      IDE hard drive standby times, to account for whether battery power is in use.

       stop   Invoked  when  the daemon stops.	Normally undoes any policy settings done when the
	      daemon started.

       suspend [ system | user ]
	      Invoked when the APM driver reports that system suspension has been initiated.  The
	      second  parameter  indicates  whether  the BIOS or a user action (such as closing a
	      laptop) initiated suspension.

	      The BIOS "suspend" mode aggressively conserves power, and normally  involves  shut-
	      ting  off  power	to all devices except the CPU core and memory, which is kept in a
	      very low power mode.  Most laptops can stay suspended, using battery  power  alone,
	      for  several days.  ("Hibernation" is a kind of super-suspend, where all that state
	      is written to disk and the machine uses even less power bcause it can turn off that
	      CPU  core,  using no battery power at all.  At this writing, Linux does not support
	      hibernation.)  PCMCIA devices should be manually suspended  using  cardctl(8),  and
	      some modular drivers may need to be unloaded.

       standby [ system | user ]
	      Invoked  when  the  APM driver reports that system standby has been initiated.  The
	      second parameter indicates whether the BIOS or a user action (such as invoking  apm
	      -s) caused this.

	      The  BIOS  "standby"  mode slightly conserves power, and leaves the machine able to
	      respond almost immediately to user activity.  Most laptops can't	stay  in  standby
	      mode  for  even a day, if they must rely on battery power.  Normally, nothing needs
	      to be done beyond what the BIOS itself will do.

       resume [ suspend | standby | critical ]
	      Invoked when the APM driver reports that system has resumed normal operation.   The
	      second parameter indicates what sort of mode it was in before, either the "suspend"
	      mode (possibly a "critical" suspend) or else "standby" mode.

	      The system clock must be updated to match the hardware clock;  this  will  normally
	      have  been handled by the kernel's APM driver.  PCMCIA devices may need to be manu-
	      ally resumed from standby using cardctl(8), and some modular drivers may need to be
	      reloaded	or  otherwise  reinitialized.	In the case of a critical suspend, system
	      state may not have been completely saved due to an emergency shutdown; applications
	      and drivers may be in a confused state.

       change power
	      This  presents a subset of the APM driver "power change" events, specifically those
	      where AC power was added or removed.  This will often modify the system wide  power
	      policy;  for  example, so that IDE hard drives aggressively enter standby mode when
	      only battery power is available.

       change battery
	      The APM driver has reported that the BIOS thinks the strength of one (or more) bat-
	      teries is "low"; at least ten minutes of power should remain.

       change capability
	      Some  change  in	the power management capabilities of the system was reported.  It
	      may have been caused by operation of some setup  utility,  or  by  the  arrival  or
	      removal of some devices.

       This  daemon  issues  a	number	of  different  log messages, most of which should be self
       explanatory.  The messages emitted for battery status need some explanation, however.  The
       information logged contains 4 fields after a "Battery" or "Charge" label:

       1) Rate of discharge (percent/minute).  Negative rates indicate charging.

       2) Time since total charge or total discharge (hh:mm:ss).  This value is only useful if it
	      reflects the time since a 100% or 0% state has been reached.  Otherwise, this  time
	      is  in  parentheses,  and  reflects the time since the last "important" apmd status
	      change such as starting the daemon, changing from AC power to battery power, and so
	      on.

       3)  Estimate of time left until total discharge (or total charge), assuming use similar to
	      that since the last resume ( or since AC was connected).	This time  is  calculated
	      by apmd itself.

       4)  Parenthetically, the percent and length of remaining battery life, as estimated by the
	      APM BIOS (which is often	a  conservative  estimate  from  an  intelligent  battery
	      itself).	This particular information is provided with most messages from this dae-
	      mon.

       This daemon supports APM BIOS 1.2 events, though it does not support some of the  advanced
       features  such as multiple batteries.  Also, there is no interaction yet with ACPI support
       as found in newer PC hardware.

OPTIONS
       -c seconds, --check seconds
	      Controls how many seconds to block on the /dev/apm_bios device.  Normally the  dae-
	      mon  blocks  until  the  APM driver reports an event; this number may be changed to
	      cause battery charge or discharge rates to be checked more often.

       -P proxy_cmd, --apmd_proxy proxy_cmd
	      Identifies the command to invoke when certain APM driver events are reported.   See
	      above for information about the arguments to this script.

       -p percent_change, --percentage percent_change
	      Every  time  the	percentage  of available power changes (discharge or recharge) by
	      percent_change, log information.	The default is 5.  Use values greater than 100 to
	      disable this feature.

       -V, --version
	      Print the daemon's version and exit.

       -v, --verbose
	      Enables verbose mode, where each event reported by the APM driver is logged.

       -W, --wall
	      In  addition to logging low battery status (as determined either by the -w level or
	      by the APM BIOS) using syslog(2), also use wall(1) to alert  all	users.	 This  is
	      most  useful  if syslogd(8) is not set up to write ALERT messages to all users.  If
	      both methods are used, more warnings will be made during the critical time period.

       -w warn_percent, --warn warn_percent
	      When the battery is not being charged and the percentage of available  power  drops
	      below warn_percent, log a warning at ALERT level to syslog(2).  If the -W or --wall
	      flag was given, the daemon will also use wall(1) to alert all  users  of	impending
	      doom.   Give the warning each time the percentage changes.  The default is 10.  Use
	      negative values to disable this feature.

       -q, --quiet
	      Disables the warnings identified by the -W and -w options.  (The APM BIOS  on  many
	      machines	will  provide  an  audible  warning when power is about to be used up, so
	      those extra warnings may not be needed.)

       -?, --help
	      Prints a usage message and exits.

       New software should only use the proxy script, rather than  the	following  now-deprecated
       options	(most  of  which  have never appeared in a production release).  If they are pro-
       vided, they take precedence over any proxy command invocation for each event.

       -a ac_online_cmd, --ac_online ac_online_cmd
	      Provides a command to be run when AC power becomes available, though not	when  the
	      daemon first starts.

       -b ac_offline_cmd, --ac_offline ac_offline_cmd
	      Provides a command to be run when the machine is operating on battery power, though
	      not when the daemon first starts.

       -l low_battery_cmd, --low_battery low_battery_cmd
	      Provides a command to be run when the APM BIOS judges that battery power is "low".

       -s pre_suspend_cmd, --pre_suspend pre_suspend_cmd
	      Provides a command to be run before suspending through the driver.

       -r post_resume_cmd, --post_resume post_resume_cmd
	      Provides a command to be run after resuming through the driver.

       -u, --utc
	      (This option is now completely ignored.  Edit apmd_proxy instead.)  This means  the
	      BIOS  clock  is  set  to	UTC (GMT), so the daemon should pass the -u option to the
	      clock or hwclock program when coming  out  of  suspend  or  resume  mode,  or  when
	      responding to the BIOS update time event.

BUGS
       The  first  status report printed after a power change may be inaccurate because the power
       change occured at a fractional percentage that was rounded  to  a  full	percentage.   For
       example,  say  you  are discharging the machine and have 50.9% power, which is reported as
       50%.  When you start to charge the machine, it will only have 0.1% left	before	the  per-
       centage flips to 51%, and the charge rate will be dramatically over-estimated.

       There  needs  to  be  a	more general hook to let other applications participate in system
       power management decisions and policies.

       Multiple batteries are currently treated as if they were just one large one.

FILES
       /dev/apm_bios
       /proc/apm
       /etc/apmd/apmd_proxy

AUTHOR
       This program was written by Rik Faith (faith@cs.unc.edu) and  may  be  freely  distributed
       under  the  terms  of the GNU General Public License.  There is ABSOLUTELY NO WARRANTY for
       this program.  The current maintainer is Avery Pennarun (apenwarr@worldvisions.ca).

SEE ALSO
       apm(1), xapm(1), cardctl(8), hdparm(8), syslogd(8)

					   10 Jun 1999					  APMD(8)


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