POWER.CONF(4)POWER.CONF(4)NAMEpower.conf - Power Management configuration information file
SYNOPSIS
/etc/power.conf
DESCRIPTION
The power.conf file is used by the Power Management configuration pro‐
gram pmconfig(1M), to initialize the settings for Power Management. If
you make changes to this file, you must run pmconfig(1M) manually for
the changes to take effect.
The dtpower(1M) GUI allows the configuration of a subset of parameters
allowed by this file. For ease-of-use, it is recommended that you use
dtpower(1M) to configure the parameters. See the EXAMPLES section for
information on disabling Power Management.
Power Management addresses two specific management scenarios: manage‐
ment of individual devices and management of the whole system. An indi‐
vidual device is power managed if the device supports multiple power
levels and if the device driver uses Power Management interfaces pro‐
vided by the kernel to save device power when the device is idle.
All entries in the power.conf file are processed in the order that they
occur in the file.
Automatic Device Power Management
Devices with drivers that use the automatic device Power Management
interfaces are automatically power managed if the autopm entry is
enabled. The autopm entry is described near the end of this section.
The pm-components property describes the Power Management model of a
device driver to the Power Management framework. See pm-components(9P)
for more information.
When a component has been idle at a given power level for its threshold
time, the power level of the component is reduced to the next lower
power level of that component, if any. For devices which implement mul‐
tiple components, each component is power-managed independently.
Default thresholds for components of automatically power managed
devices are computed by the Power Management framework based on the
system idleness threshold. By default, all components of the device are
powered off if they have all been idle for the system's idleness
threshold. The default system idleness threshold is determined by the
applicable United States Environmental Protection Agency's (EPA) Energy
Star Memorandum of Understanding. See the NOTES section of this manual
page for more information.
To set the system idleness threshold, use one of the following entries:
system-threshold threshold
system-threshold always-on
where threshold is the value of the system idleness threshold in hours,
minutes or seconds as indicated by a trailing h, m or s (defaulting to
seconds if only a number is given). If always-on is specified, then by
default, all devices are left at full power.
The system-threshold entry is applicable to CPU Power Management only
when CPU Power Management has been configured to operate in poll-mode,
which is expressed through the cpupm keyword.
If a system has power manageable CPUs, these can be managed indepen‐
dently of the system idleness threshold by using one of the following
entries:
cpu-threshold threshold
cpu-threshold always-on
where threshold is the value of the CPU idleness threshold in hours,
minutes or seconds as indicated by a trailing h, m or s (defaulting to
seconds if only a number is given). If always-on is specified, then by
default, all CPUs are left at full power.
The cpu-threshold keyword is used only when CPU Power Management has
been configured to operate in poll-mode, which is expressed through the
cpupm keyword.
If no cpu-threshold entry is specified, then the system idleness
threshold is used.
To override the default device component thresholds assigned by the
Power Management framework, a device-thresholds entry can be used. A
device-thresholds entry sets thresholds for a specific automatically
power-managed device or disables automatic Power Management for the
specific device.
A device-thresholds entry has the form:
device-thresholds phys_path (threshold ...) ...
or
device-thresholds phys_path threshold
or
device-thresholds phys_path always-on
where phys_path specifies the physical path (libdevinfo(3LIB)) of a
specific device. For example,
/pci@8,600000/scsi@4/ssd@w210000203700c3ee,0 specifies the physical
path of a disk. A symbolic link into the /devices tree, for example
/dev/dsk/c1t1d0s0, is also accepted. The thresholds apply (or keeping
the device always on applies) to the specific device only.
In the first form above, each threshold value represents the number of
hours, minutes or seconds, depending on a trailing h, m or s with a
default to seconds, to spend idle at the corresponding power level
before power is reduced to the next lower level of that component.
Parentheses are used to group thresholds per component, with the first
(leftmost) group being applied to component 0, the next to component 1,
and the like. Within a group, the last (rightmost) number represents
the time to be idle in the highest power level of the component before
going to the next-to-highest level, while the first (leftmost) number
represents the time to be idle in the next-to-lowest power level before
going to the lowest power level.
If the number of groups does not match the number of components
exported by the device (by means of pm-components(9P) property), or the
number of thresholds in a group is not one less than the number of
power levels the corresponding component supports, then an error mes‐
sage is printed and the entry is ignored.
For example, assume a device called xfb exports the components Frame
Buffer and Monitor. Component Frame Buffer has two power levels: Off
and On. Component Monitor has four power levels: Off, Suspend, Standby,
and On.
The following device-thresholds entry:
device-thresholds /pci@f0000/xfb@0 (0) (3m 5m 15m)
would set the threshold time for the Monitor component of the specific
xfb card to go from On to Standby in 15 minutes, the threshold for Mon‐
itor to go from Standby to Suspendin 5 minutes, and the threshold for
Monitor to go from Suspend to Off in 3 minutes. The threshold for Frame
Buffer to go from On to Off is 0 seconds.
In the second form above, where a single threshold value is specified
without parentheses, the threshold value represents a maximum overall
time within which the entire device should be powered down if it is
idle. Because the system does not know about any internal dependencies
there can be among a device's components, the device can actually be
powered down sooner than the specified threshold, but does take longer
than the specified threshold, provided that all device components are
idle.
In the third form above, all components of the device are left at full
power.
Device Power Management entries are only effective if there is no user
process controlling the device directly. For example, X Windows systems
directly control frame buffers. The entries in the power.conf file are
effective only when X Windows is not running.
Dependencies among devices can also be defined. A device depends upon
another if none of its components might have their power levels reduced
unless all components of the other device are powered off. A dependency
can be indicated by an entry of the form:
device-dependency dependent_phys_path phys_path [ phys_path ... ]
where dependent_phys_path is the path name (as above) of the device
that is kept up by the others, and the phys_path entries specify the
devices that keep it up. A symbolic link into the /devices tree, such
as /dev/fb, is also accepted. This entry is needed only for logical
dependents for the device. A logical dependent is a device that is not
physically connected to the power managed device (for example, the dis‐
play and the keyboard). Physical dependents are automatically consid‐
ered and need not be included.
In addition to listing dependents by physical path, an arbitrary group
of devices can be made dependent upon another device by specifying a
property dependency using the following syntax:
device-dependency-property property phys_path [phys_path ...]
where each device that exports the property property is kept up by the
devices named by phys_path(s). A symbolic link into the /devices tree
(such as /dev/fb) is accepted as well as a pathname for phys_path.
For example, the following entry ensures that every device that exports
the boolean property named removable-media is kept up when the console
framebuffer is up. See removable-media(9P).
# This entry keeps removable media from being powered down unless the
# console framebuffer and monitor are powered down
# (See removable-media(9P))
#
device-dependency-property removable-media /dev/fb
An autopm entry can be used to enable or disable automatic device Power
Management on a system-wide basis. The format of the autopm entry is:
autopm behavior
Acceptable behavior values are described as follows:
default
The behavior of the system depends upon its model. Desktop
models that fall under the United States Environmental Pro‐
tection Agency's Energy Star Memorandum of Understanding #3
have automatic device Power Management enabled, and all oth‐
ers do not. See the NOTES section of this manual page for
more information.
enable
Automatic device Power Management is started when this entry
is encountered.
disable
Automatic device Power Management is stopped when this entry
is encountered.
A cpupm entry can be used to enable or disable Power Management of CPUs
on a system-wide basis, independent of autopm. The format of the cpupm
entry is:
cpupm behavior
Acceptable behavior values and their meanings are :
enable
CPU Power Management is started when this entry is encoun‐
tered.
Where the behavior is enable, an optional mode argument can
be specified:
cpupm enable mode
Acceptable mode values and their meanings are:
event-mode
CPU power state transitions is driven by
thread scheduler/dispatcher events. The cpu-
threshold, and system-threshold keywords are
not used for CPUs in this mode.
poll-mode
The Power Management framework polls the idle‐
ness of the system's CPUs, and manages their
power once idle for the period of time speci‐
fied by either the system-threshold or cpu-
threshold.
disable
CPU Power Management is stopped when this entry is encoun‐
tered.
If supported by the platform, a cpu_deep_idle entry can be used to
enable or disable automatic use of power saving cpu idle states. The
format of the cpu_deep_idle entry is:
cpu_deep_idle behavior
Acceptable values for behavior are:
default
Advanced cpu idle power saving features are enabled on hard‐
ware which supports it. On X86 systems this can translate to
the use of ACPI C-States beyond C1.
enable
Enables the system to automatically use idle cpu power sav‐
ing features.
disable
The system does not automatically use idle cpu power saving
features. This option can be used when maximum performance
is required at the expense of power.
absent
It the cpu_deep_idle keyword is absent from power.conf the
behavior is the same as the default case.
Once every device is at its lowest possible power state, additional
power savings can be obtained by putting the system into a sleep state
(if the platform hardware is capable of doing so).
S3 Support
Because of reliability problems encountered in BIOS implementations of
X86 systems not produced by Sun Microsystems, by default, only X86
workstation products produced by Sun are considered to support S3 (sus‐
pend to RAM). To override this default, an S3-support entry (of the
format S3-support behavior) can be used to indicate if the system sup‐
ports S3.
Acceptable behavior values are:
enable
The system supports entry into S3 state. If the BIOS of a
system enabled using an S3-support enable entry does not
support entry into S3, the attempt fails and the system
returns to normal operation. If support for S3 in the BIOS
of a system enabled via an S3-support entry contains bugs,
the system can be unable to enter S3 or resume successfully,
so use this entry with caution.
disable
The system does not support entry into S3 state.
Automatic Entry Into S3
If supported by your platform, an autoS3 entry can be used to enable or
disable automatic entry into the S3 state. When in the S3 state, the
power button, keyboard and mouse activity or network traffic (depending
upon the capabilities of the platform hardware) can wake the system,
returning it to the state it was in upon entry to the S3 state. If the
platform doesn't support S3, the entry has no effect.
The format of the autoS3 entry is autoS3 behavior.
Acceptable behavior values are:
default
System behavior depends upon model. Sun X86 desktop and
workstation models that fall under the United States Envi‐
ronmental Protection Agency's Energy Star Memorandum of
Understanding #3 have automatic entry into the S3 state
enabled. Non-Sun systems do not. See NOTES for more informa‐
tion.
enable
Enables the system to automatically enter the S3 state if
autopm is enabled and every device is at its lowest power
state.
disable
The system does not automatically enter the S3 state.
System Power Management
The system Power Management entries control Power Management of the
entire system using the suspend-resume feature. When the system is sus‐
pended, the complete current state is saved on the disk before power is
removed. On reboot, the system automatically starts a resume operation
and the system is restored to the state it was in prior to suspend.
The system can be configured to do an automatic shutdown (autoshutdown)
using the suspend-resume feature by an entry of the following form:
autoshutdown idle_time start_time finish_time behavior
idle_time specifies the time in minutes that system must have been idle
before it is automatically shutdown. System idleness is determined by
the inactivity of the system and can be configured as discussed below.
start_time and finish_time (each in hh:mm) specify the time period dur‐
ing which the system can be automatically shutdown. These times are
measured from the start of the day (12:00 a.m.). If the finish_time is
less than or equal to the start_time, the period span from midnight to
the finish_time and from the start_time to the following midnight. To
specify continuous operation, the finish_time can be set equal to the
start_time.
Acceptable behavior values are described as follows:
shutdown
The system is shut down automatically when it has been
idle for the number of minutes specified in the
idle_time value and the time of day falls between the
start_time and finish_time values.
noshutdown
The system is never shut down automatically.
autowakeup
If the hardware has the capability to do autowakeup,
the system is shut down as if the value were shutdown
and the system is restarted automatically the next time
the time of day equals finish_time.
default
The behavior of the system depends upon its model.
Desktop models that fall under the United States Envi‐
ronmental Protection Agency's Energy Star Memorandum of
Understanding #2 have automatic shutdown enabled, as if
behavior field were set to shutdown, and all others do
not. See NOTES.
unconfigured
The system does not be shut down automatically. If the
system has just been installed or upgraded, the value
of this field is changed upon the next reboot.
You can use the following format to configure the system's notion of
idleness:
idleness_parameter value
Where idleness_parameter can be:
ttychars
If the idleness_parameter is ttychars, the value field
is interpreted as the maximum number of tty characters
that can pass through the ldterm module while still
allowing the system to be considered idle. This value
defaults to 0 if no entry is provided.
loadaverage
If the idleness_parameter is loadaverage, the (floating
point) value field is interpreted as the maximum load
average that can be seen while still allowing the system
to be considered idle. This value defaults to 0.04 if no
entry is provided.
diskreads
If the idleness_parameter is diskreads, the value field
is interpreted as the maximum number of disk reads that
can be perform by the system while still allowing the
system to be considered idle. This value defaults to 0
if no entry is provided.
nfsreqs
If the idleness_parameter is nfsreqs, the value field is
interpreted as the maximum number of NFS requests that
can be sent or received by the system while still allow‐
ing the system to be considered idle. Null requests,
access requests, and getattr requests are excluded from
this count. This value defaults to 0 if no entry is pro‐
vided.
idlecheck
If the idleness_parameter is idlecheck, the value must
be pathname of a program to be executed to determine if
the system is idle. If autoshutdown is enabled and the
console keyboard, mouse, tty, CPU (as indicated by load
average), network (as measured by NFS requests) and disk
(as measured by read activity) have been idle for the
amount of time specified in the autoshutdown entry spec‐
ified above, and the time of day falls between the start
and finish times, then this program is executed to check
for other idleness criteria. The value of the idle time
specified in the above autoshutdown entry is passed to
the program in the environment variable PM_IDLETIME. The
process must terminate with an exit code that represents
the number of minutes that the process considers the
system to have been idle.
There is no default idlecheck entry.
When the system is suspended, the current system state is saved on the
disk in a statefile. An entry of following form can be used to change
the location of statefile:
statefile pathname
where pathname identifies a block special file, for example,
/dev/dsk/c1t0d0s2, or is the absolute pathname of a local ufs file. If
the pathname specifies a block special file, it can be a symbolic link
as long as it does not have a file system mounted on it. If pathname
specifies a local ufs file, it cannot be a symbolic link. If the file
does not exist, it is created during the suspend operation. All the
directory components of the path must already exist.
The actual size of statefile depends on a variety of factors, including
the size of system memory, the number of loadable drivers/modules in
use, the number and type of processes running, and the amount of user
memory that has been locked down. It is recommended that statefile be
placed on a file system with at least 10 Mbytes of free space. In case
there is no statefile entry at boot time, an appropriate new entry is
automatically created by the system.
EXAMPLES
Example 1 Disabling Automatic Device Power Management
To disable automatic device Power Management, change the following line
in the /etc/power.conf file
autopm default
to read:
autopm disable
Then run pmconfig or reboot. See pmconfig(1M) for more information.
You can also use dtpower to disable automatic device Power Management.
See dtpower(1M) for more information.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
┌─────────────────────┬─────────────────┐
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├─────────────────────┼─────────────────┤
│Interface stability │ Committed │
└─────────────────────┴─────────────────┘
SEE ALSOpmconfig(1M), powerd(1M), sys-unconfig(1M), uadmin(2), libdev‐
info(3LIB), attributes(5), cpr(7), ldterm(7M), pm(7D), pm-compo‐
nents(9P), removable-media(9P)
Writing Device Drivers
Solaris Common Desktop Environment: User's Guide
NOTES
SPARC desktop models first shipped after October 1, 1995 and before
July 1, 1999 comply with the United States Environmental Protection
Agency's Energy Star Memorandum of Understanding #2 guidelines and have
autoshutdown enabled by default after 30 minutes of system idleness.
This is achieved by default keyword of autoshutdown entry behave as
shutdown for these machines. The user is prompted to confirm this
default behavior at system installation reboot, or during the first
reboot after the system is unconfigured by sys-unconfig(1M).
SPARC desktop models first shipped after July 1, 1999 comply with the
United States Environmental Protection Agency's Energy Star Memorandum
of Understanding #3 guidelines and have autoshutdown disabled by
default, with autopm enabled after 30 minutes of idleness. This is
achieved by interpreting default keyword of autopm entry behavior as
enabled for these machines. User is not prompted to confirm this
default behavior.
To determine the version of the EPA's Energy Star Memorandum applicable
to your machine, use:
prtconf -pv | grep -i energystar
Absence of a property indicates no Energy Star guidelines are applica‐
ble to your machine.
System Power Management ( suspend-resume) is currently supported only
on a limited set of hardware platforms. See the Solaris Common Desktop
Environment: User's Guide for a complete list of platforms that support
system Power Management. See uname(2) to programmatically determine if
the machine supports suspend-resume.
Sun X86 desktop models first shipped after July 1, 1999 fall within
United States Environmental Protection Agency's Energy Star Memorandum
of Understanding #3 guidelines and have autopm and autoS3 enabled by
default, with entry into S3 after 30 minutes of idleness. This is
achieved by interpreting the default keyword of the autopm and autoS3
behaviors as enabled for these machines. You are not prompted to con‐
firm the default behavior. On all other X86 systems, the autopm and
autoS3 default keywords are interpreted as disable.
Feb 27, 2009 POWER.CONF(4)
