Capacity and lifetime of laptop batteries has improved much in the last years. Nevertheless modern processors consume much more energy than older ones and each laptop generation introduces more devices hungry for energy. That's why Power Management is more important than ever. Increasing battery run time doesn't necessarily mean buying another battery. Much can be achieved applying intelligent Power Management policies.

Please notice that this guide describes Power Management for laptops. While some sections might also suite for servers, others do not and may even cause harm. Please do not apply anything from this guide to a server unless you really know what you are doing.

As this guide has become rather long, here's a short overview helping you to find your way through it.

The Prerequisites chapter talks about some requirements that should be met before any of the following device individual sections will work. This includes BIOS settings, kernel configuration and some simplifications in user land. The following three chapters focus on devices that typically consume most energy - processor, display and hard drive. Each can be configured seperately. CPU Power Management shows how to adjust the processor's frequency to save a maximum of energy whithout losing too much performance. A few different tricks prevent your hard drive from working unnecessarily often in Disk Power Management (decreasing noise level as a nice side effect). Some notes on Wireless LAN and USB finish the device section in Power Management for other devices while another chapter is dedicated to the (rather experimental) sleep states. Last not least Troubleshooting lists common pitfalls.

Before going into the details on making individual devices Power Management aware, make sure certain requirements are met. After controlling the BIOS settings, some kernel options want to be enabled - these are in short ACPI, sleep states and CPU frequency scaling. As power saving most of the time comes along with performance loss or increased latency, it should only be enabled when running on batteries. That's where a new runlevel battery comes in handy.

First have a look into your BIOS Power Management settings. The best way is to combine BIOS and operating system policies, but for the moment it's better to disable most of the BIOS part. This makes sure it doesn't interfere with your policies. Don't forget to re-check BIOS settings after you configured everything else.

ACPI (Advanced Configuration and Power Interface) support in the kernel is still work in progress. Using a recent kernel will make sure you'll get the most out of it.

In kernel config, activate at least these options:

Power Management Options --->
  [*] Power Management Support
  [ ] Software Suspend
  [ ] Suspend-to-Disk Support

  ACPI( Advanced Configuration and Power Interface ) Support --->
    [*] ACPI Support
    [ ]   Sleep States
    [*]   AC Adapter
    [*]   Battery
    <M>   Button
    <M>   Fan
    <M>   Processor
    <M>     Thermal Zone
    < >   ASUS/Medion Laptop Extras
    < >   Toshiba Laptop Extras
    [ ]   Debug Statements
    
  CPU Frequency Scaling --->
    [*] CPU Frequency scaling
          Default CPUFreq governor (userspace)
    <*>   'performance' governor
    <*>   'powersave' governor
    <*>   'ondemand' cpufreq policy governor
    <*>   CPU frequency table helpers
    <M> ACPI Processor P-States driver
    <*> CPUFreq driver for your processor

Decide yourself whether you want to enable Software Suspend, Suspend-to-Disk and Sleep States (see below). If you own an ASUS, Medion or Toshiba laptop, enable the appropriate section.

The kernel has to know how to enable CPU frequency scaling on your processor. As each type of CPU has a different interface, you've got to choose the right driver for your processor. Be careful here - enabling Intel Pentium 4 clock modulation on a Pentium M system will lead to strange results for example. Consult the kernel documentation if you're unsure which one to take.

Compile your kernel, make sure the right modules get loaded at startup and boot into your new ACPI-enabled kernel. Next run emerge sys-power/acpid to get the acpi daemon. This one informs you about events like switching from AC to battery or closing the lid. Make sure the modules are loaded if you didn't compile them into the kernel and start acpid by executing /etc/init.d/acpid start. Run rc-update add acpid default to load it on startup. You'll soon see how to use it.

# emerge sys-power/acpid
# /etc/init.d/acpid start
# rc-update add acpid default

The default policy will be to enable Power Management only when needed - running on batteries. To make the switch between AC and battery convenient, create a runlevel battery that holds all the scripts starting and stopping Power Management.

# cd /etc/runlevels
# cp -a default battery

Finished. Your new runlevel battery contains everything like default, but there is no automatic switch between both yet. Time to change it.

Typical ACPI events are closing the lid, changing the power source or pressing the sleep button. An important event is changing the power source, which should cause a runlevel switch. Create the following files to switch between default and battery runlevel depending on the power source:

#!/bin/bash

# BEGIN configuration
RUNLEVEL_AC="default"
RUNLEVEL_BATTERY="battery"
# END configuration


if [ ! -d "/etc/runlevels/${RUNLEVEL_AC}" ]
then
        logger "${0}: Runlevel ${RUNLEVEL_AC} does not exist. Aborting."
        exit 1
fi

if [ ! -d "/etc/runlevels/${RUNLEVEL_BATTERY}" ]
then
        logger "${0}: Runlevel ${RUNLEVEL_BATTERY} does not exist. Aborting."
        exit 1
fi

if on_ac_power
then
    if [[ "$(cat /var/lib/init.d/softlevel)" != "${RUNLEVEL_AC}" ]]
  then
            logger "Switching to ${RUNLEVEL_AC} runlevel"
            /sbin/rc ${RUNLEVEL_AC}
        fi
elif [[ "$(cat /var/lib/init.d/softlevel)" != "${RUNLEVEL_BATTERY}" ]]
then
        logger "Switching to ${RUNLEVEL_BATTERY} runlevel"
        /sbin/rc ${RUNLEVEL_BATTERY}
fi

# replace "ac_adapter" below with the event generated on your laptop
# See /var/log/acpid
event=ac_adapter.*
action=/etc/acpi/actions/pmg_switch_runlevel.sh %e

# replace "battery" below with the event generated on your laptop
# See /var/log/acpid
event=battery.*
action=/etc/acpi/actions/pmg_switch_runlevel.sh %e

Additionally you need the package sys-power/powermgmt-base which contains the on_ac_power utility. The file pmg_switch_runlevel.sh must be executable.

# emerge powermgmt-base
# chmod +x /etc/acpi/actions/pmg_switch_runlevel.sh
# /etc/init.d/acpid restart

Give it a try: Plug AC in and out and watch syslog for the "Switching to AC mode" or "Switching to battery mode" messages. See the Troubleshooting section if the script is not able to detect the power source correctly.

Due to the nature of the event mechanism, your laptop will boot into runlevel default regardless of the AC/battery state. You can add another entry to the boot loader with softlevel=battery, but it's likely to forget choosing it. A better way is faking an ACPI event in the end of the boot process and let the /etc/acpi/default.sh script decide whether a runlevel change is necessary. Open /etc/conf.d/local.start in your favourite editor and add these lines:

# Fake acpi event to switch runlevel if running on batteries
/etc/acpi/actions/pmg_switch_runlevel.sh "battery/battery"

Prepared like this you can activate Power Management policies for individual devices.

CPU frequency scaling brings up some technical terms that might be unknown to you. Here's a quick introduction.

First of all, the kernel has to be able to change the processor's frequency. The CPUfreq processor driver knows the commands to do it on your CPU. Thus it's important to choose the right one in your kernel. You should already have done it above. Once the kernel knows how to change frequencies, it has to know which frequency it should set. This is done according to the policy which consists of a CPUfreq policy and a governor. A CPUfreq policy are just two numbers which define a range the frequency has to stay between - minimal and maximal frequency. The governor now decides which of the available frequencies in between minimal and maximal frequency to choose. For example, the powersave governor always chooses the lowest frequency available, the performance governor the highest one. The userspace governor makes no decision but chooses whatever the user (or a program in userspace) wants - which means it reads the frequency from /sys/devices/system/cpu/cpu0/cpufreq/scaling_setspeed.

This doesn't sound like dynamic frequency changes yet and in fact it isn't. Dynamics however can be accomplished with various approaches. For example, the ondemand governor makes its decisions depending on the current CPU load. The same is done by various userland tools like cpudyn, cpufreqd, powernowd and many more. ACPI events can be used to enable or disable dynamic frequency changes depending on power source.

Decreasing CPU speed and voltage has two advantages: On the one hand less energy is consumed, on the other hand there is thermal improvement as your system doesn't get as hot as running on full speed. The main disadvantage is obviously the loss of performance. Decreasing processor speed is a trade off between performance loss and energy saving.

It's time to test whether CPU frequency changing works. Let's install another tool which is very handy for debugging purposes: sys-power/cpufrequtils

# emerge cpufrequtils
# cpufreq-info

Here is an example output:

cpufrequtils 0.2: cpufreq-info (C) Dominik Brodowski 2004
Report errors and bugs to linux@brodo.de, please.
analyzing CPU 0:
  driver: centrino
  CPUs which need to switch frequency at the same time: 0
  hardware limits: 600 MHz - 1.40 GHz
  available frequency steps: 600 MHz, 800 MHz, 1000 MHz, 1.20 GHz, 1.40 GHz
  available cpufreq governors: ondemand, powersave, userspace, performance
  current policy: frequency should be within 924 MHz and 1.40 GHz.
    The governor "performance" may decide which speed to use
    within this range.
  current CPU frequency is 1.40 GHz (asserted by call to hardware).

Now play around with cpufreq-set to make sure frequency switching works. Run cpufreq-set -g ondemand for example to activate the ondemand governor and verify the change with cpufreq-info. If it doesn't work as expected, you might find help in the Troubleshooting section in the end of this guide.

The above is quite nice, but not doable in daily life. Better let your system set the appropriate frequency automatically. There are many different approaches to do this. The following table gives a quick overview to help you decide on one of them. It's roughly seperated in three categories kernel for approaches that only need kernel support, daemon for programs that run in the background and graphical for programs that provide a GUI for easy configuration and changes.

While adjusting the frequency to the current load looks simple on the first view, it's not such a trivial task. A bad algorithm can cause switching between two frequencies all the time or wasting energy when setting frequency to an unnecessary high level.

Which one to choose? If you have no idea about it, try cpufreqd:

# emerge cpufreqd

cpufreqd can be configured by editing /etc/cpufreqd.conf. The default one that ships with cpufreqd may look a bit confusing. I recommend replacing it with the one from Gentoo developer Henrik Brix Andersen (see below).

[General]
pidfile=/var/run/cpufreqd.pid
poll_interval=2
pm_type=acpi
verbosity=5

[Profile]
name=ondemand
minfreq=0%
maxfreq=100%
policy=ondemand

[Profile]
name=powersave
minfreq=0%
maxfreq=100%
policy=powersave

[Profile]
name=performance
minfreq=0%
maxfreq=100%
policy=performance

[Rule]
name=battery
ac=off
profile=ondemand

[Rule]
name=battery_low
ac=off
battery_interval=0-10
profile=powersave

[Rule]
name=ac
ac=on
profile=performance

You can't use a percentage value like above for min_freq and max_freq if you are using kernel 2.6 with the sysfs interface (you probably do). Replace it with the lowest and highest frequency as reported by cpufreq-info --hwlimits. For example, on my 1.4 GHz Pentium M I put in

minfreq=600000
maxfreq=1400000

Last not least start the daemon.

# rc-update add cpufreqd default battery
# rc

The last thing to check is that your new policies do a good job. An easy way to do so is monitoring CPU speed while working with your laptop:

# watch grep \"cpu MHz\" /proc/cpuinfo

If /proc/cpuinfo doesn't get updated (see Troubleshooting), monitor the CPU frequency with:

# watch x86info -mhz

Depending on your setup, CPU speed should increase on heavy load, decrease on no activity or just stay at the same level. When using cpufreqd and verbosity set to 5 or higher in cpufreqd.conf you'll get additional information about what's happening reported to syslog.

As you can see in figure 1.1, the LCD display consumes the biggest part of energy (might not be the case for non-mobile CPU's). Thus it's quite important not only to shut the display off when not needed, but also to reduce it's backlight if possible. Most laptops offer the possibility to control the backlight dimming.

First thing to check is the standby/suspend/off timings of the display. As this depends heavily on your windowmanager, I'll let you figure it out yourself. Just two common places: Blanking the terminal can be done with setterm -blank <number-of-minutesM>, setterm -powersave on and setterm -powerdown <number-of-minutesM>. For Xorg, modify /etc/X11/xorg.conf similar to this:

Section "ServerLayout"
  Identifier  [...]
  [...]
  Option  "BlankTime"  "5"  # Blank the screen after 5 minutes (Fake)
  Option  "StandbyTime"  "10"  # Turn off screen after 10 minutes (DPMS)
  Option  "SuspendTime"  "20"  # Full suspend after 20 minutes
  Option  "OffTime"  "30"  # Turn off after half an hour
  [...]
EndSection

[...]

Section "Monitor"
  Identifier  [...]
  Option  "DPMS"  "true"
  [...]
EndSection

This is the same for XFree86 and /etc/X11/XF86Config.

Probably more important is the backlight dimming. If you have access to the dimming settings via a tool, write a small script that dims the backlight in battery mode and place it in your battery runlevel. The following script should work on most IBM Thinkpads. It needs the app-laptop/ibm-acpi package or the appropriate option in your kernel has to be enabled.

To be able to set the brightness level, the ibm_acpi module has to be loaded with the experimental parameter.

(Please read the warnings above before doing this!)
# emerge ibm-acpi
# echo "options ibm_acpi experimental=1" >> /etc/modules.d/ibm_acpi
# /sbin/modules-update
# echo ibm_acpi >> /etc/modules.autoload.d/kernel-2.6
# modprobe ibm_acpi

This should work without error messages and a file /proc/acpi/ibm/brightness should be created after loading the module. An init script will take care of choosing the brightness according to the power source.

# See /proc/acpi/ibm/brightness for available values
# Please read /usr/share/doc/ibm-acpi-*/README.gz

# brigthness level in ac mode. Default is 7.
BRIGHTNESS_AC=7

# brightness level in battery mode. Default is 4.
BRIGHTNESS_BATTERY=4

#!/sbin/runscript

set_brightness() {
    if on_ac_power
    then
        LEVEL=${BRIGHTNESS_AC:-7}
    else
        LEVEL=${BRIGHTNESS_BATTERY:-4}
    fi

    if [ -f /proc/acpi/ibm/brightness ]
    then
        ebegin "Setting LCD brightness"
        echo "level ${LEVEL}" > /proc/acpi/ibm/brightness
        eend $?
    else
        ewarn "Setting LCD brightness is not supported."
        ewarn "Check that ibm_acpi is loaded into the kernel"
    fi
}

start() {
    set_brightness
}

stop () {
    set_brightness
}

When done, make sure brightness is adjusted automatically by adding it to the battery runlevel.

# chmod +x /etc/init.d/lcd-brightness
# rc-update add lcd-brightness battery
# rc

Let's bring the hard disk to sleep as early as possible whenever it is not needed. I'll show you two possibilities to do it. First cpudyn supports Disk Power Management. Uncomment the lines in the "Disk Options" section in /etc/conf.d/cpudyn. To put your first disk to sleep after 60 seconds of no activity, you would modify it like this:

################################################
# DISK OPTIONS
# (disabled by default)
################################################

#
# Timeout to put the disk in standby mode if there was no
# io during that period (in seconds)
#

TIMEOUT=60

#
# Specified disks to spindown (comma separated devices)
#

DISKS=/dev/hda

The second possibility is using a small script and hdparm. Create /etc/init.d/pm.hda like this:

#!/sbin/runscript

depend() {
  after hdparm
}

start() {
  ebegin "Activating Power Management for Hard Drives"
  hdparm -q -S12 /dev/hda
  eend $?
}

stop () {
  ebegin "Deactivating Power Management for Hard Drives"
  hdparm -q -S253 /dev/hda
  eend $?
}

See man hdparm for the options. If your script is ready, add it to the battery runlevel.

# chmod +x /etc/init.d/pm.hda
# /sbin/depscan.sh
# rc-update add pm.hda battery

Recent kernels (2.6.6 and greater, recent 2.4 ones and others with patches) include the so-called laptop-mode. When activated, dirty buffers are written to disk on read calls or after 10 minutes (instead of 30 seconds). This minimizes the time the hard disk needs to be spun up.

# emerge laptop-mode-tools

laptop-mode-tools has it's configuration file in /etc/laptop-mode/laptop-mode.conf. Adjust it the way you like it, it's well commented. Run rc-update add laptop_mode battery to start it automatically.

Besides putting your disk to sleep state as early as possible, it is a good idea to minimize disk accesses. Have a look at processes that write to your disk frequently - the syslogd is a good candidate. You probably don't want to shut it down completely, but it's possible to modify the config file so that "unnecessary" things don't get logged and thus don't create disk traffic. Cups writes to disk periodically, so consider shutting it down and only enable it manually when needed.

# rc-update del cupsd battery

Another possibility is to deactivate swap in battery mode. Before writing a swapon/swapoff switcher, make sure there is enough RAM and swap isn't used heavily, otherwise you'll be in big problems.

If you don't want to use laptop-mode, it's still possible to minimize disk access by mounting certain directories as tmpfs - write accesses are not stored on a disk, but in main memory and get lost with unmounting. Often it's useful to mount /tmp like this - you don't have to pay special attention as it gets cleared on every reboot regardless whether it was mounted on disk or in RAM. Just make sure you have enough RAM and no program (like a download client or compress utility) needs extraordinary much space in /tmp. To activate this, enable tmpfs support in your kernel and add a line to /etc/fstab like this:

none  /tmp  tmpfs  size=32m  0 0

Wireless LAN cards consume quite a few energy. Put them in Power Management mode in analogy to the pm.hda script.

#!/sbin/runscript
start() {
  ebegin "Activating Power Management for Wireless LAN"
  iwconfig wlan0 power on power max period 3
  eend $?
}

stop () {
  ebegin "Deactivating Power Management for Wireless LAN"
  iwconfig wlan0 power off
  eend $?
}

Starting this script will put wlan0 in Power Management mode, going to sleep at the latest three seconds after no traffic. Save it as /etc/init.d/pm.wlan0 and add it to the battery runlevel like the disk script above. See man iwconfig for details and more options. If your driver and access point support changing the beacon time, this is a good starting point to save even more energy.

# chmod +x /etc/init.d/pm.wlan0
# /sbin/depscan.sh
# rc-update add pm.wlan0 battery

There are two problems with USB devices regarding energy consumption: First, devices like USB mice, digital cameras or USB sticks consume energy while plugged in. You cannot avoid this (nevertheless remove them in case they're not needed). Second, when there are USB devices plugged in, the USB host controller periodically accesses the bus which in turn prevents the CPU from going into C3/4 sleep mode. The OS answer to this problem is the so called "USB selective suspend", which has not yet been implemented in the kernel. USB selective suspend only allows bus accesses in case the device is in use. The cruel workaround until it's implemented is as following: Compile USB support and devices as modules and remove them via a script while they are not in use (e.g. when closing the lid).

ACPI defines different sleep states. The more important ones are

• S1 aka Standby
• S3 aka Suspend to RAM aka Sleep
• S4 aka Suspend to Disk aka Hibernate

They can be called whenever the system is not in use, but a shutdown is not wanted due to the long boot time.

The ACPI support for these sleep states is marked as experimental for good reason. APM sleep states seem to be more stable, however you can't use APM and ACPI together.

There are currently three implementations for S4. The original one is swsusp, then there is swsusp2 which has the nicest interface (including bootsplash support), but requires manual kernel patching. Last not least we have Suspend-to-Disk, a fork of swsusp.

If this confused you, have a look at a feature comparison. If you still are confused and don't know which one to choose, first give swsusp2 a try, it looks most promising.

The kernel part for this is as following:

Power Management Options --->

  (sleep and standby)
  ACPI( Advanced Configuration and Power Interface ) Support --->
    [*] ACPI Support
       [*]   Sleep States

  (hibernate with swsusp)
  [*] Software Suspend (EXPERIMENTAL)
  
  (hibernate with swsusp2)
  Software Suspend 2
    --- Image Storage (you need at least one writer)
    [*]    Swap Writer
    --- Page Transformers
    [*]    LZF image compression
    (/dev/"your-swap-here")    Default resume device name

  (hibernate with Suspend-to-Disk)
  [*] Suspend-to-Disk Suport
  (/dev/"your-swap-here") Default resume partition

Compile your kernel with the appropriate options enabled and issue cat /proc/acpi/sleep for 2.4 series respectively cat /sys/power/state for 2.6 to find out what is supported. The latter gives me standby mem disk. For swsusp, the kernel parameter resume=/dev/"your-swap-here" has to be appended. If booting is not possible due to a broken image, use noresume for swsusp, pmdisk=off for Suspend-to-Disk and noresume2 for swsusp2.

To put your system in one of the sleep states, use

(kernel 2.4 series)
# echo 1 > /proc/acpi/sleep          (standby)
# echo 3 > /proc/acpi/sleep          (sleep)

(kernel 2.6 series)
# echo -n standby > /sys/power/state (standby)
# echo -n mem > /sys/power/state     (sleep)

(swsusp)
# echo 4 > /proc/acpi/sleep          (hibernate)

(Suspend-to-Disk)
# echo -n disk > /sys/power/state    (hibernate)

(swsusp2)
# /usr/sbin/hibernate                   (hibernate, see below)

If you experience kernel panics due to uhci or similar, try to compile USB support as module and unload the modules before sending your laptop to sleep mode.

While the above should be sufficient to get swsusp and Suspend-to-Disk running (I didn't say working), swsusp2 needs special care. The first thing to do is patching the kernel with the patches provided at http://softwaresuspend.berlios.de/. Additionally you've got to emerge hibernate-script. Once it is installed, configure /etc/hibernate/hibernate.conf and try whether it works:

# emerge hibernate-script
# $EDITOR /etc/hibernate/hibernate.conf
(Last chance to backup any data)
# hibernate

Q: I'm trying to change the CPU frequency, but /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor does not exist.

A: Make sure your processor supports CPU frequency scaling and you chose the right CPUFreq driver for your processor. Here is a list of processors that are supported by cpufreq (kernel 2.6.7): ARM Integrator, ARM-SA1100, ARM-SA1110, AMD Elan - SC400, SC410, AMD mobile K6-2+, AMD mobile K6-3+, AMD mobile Duron, AMD mobile Athlon, AMD Opteron, AMD Athlon 64, Cyrix Media GXm, Intel mobile PIII and Intel mobile PIII-M on certain chipsets, Intel Pentium 4, Intel Xeon, Intel Pentium M (Centrino), National Semiconductors Geode GX, Transmeta Crusoe, VIA Cyrix 3 / C3, UltraSPARC-III, SuperH SH-3, SH-4, several "PowerBook" and "iBook2" and various processors on some ACPI 2.0-compatible systems (only if "ACPI Processor Performance States" are available to the ACPI/BIOS interface).

Q: My laptop supports frequency scaling, but /sys/devices/system/cpu/cpu0/cpufreq/ is empty.

A: Look for ACPI related error messages with dmesg | grep ACPI. Try to update the BIOS, especially if a broken DSDT is reported. You can also try to fix it yourself (which is beyond the scope of this guide).

Q: My laptop supports frequency scaling, but according to /proc/cpuinfo the speed never changes.

A: Probably you have activated symmetric multiprocessing support (CONFIG_SMP) in your kernel. Deactivate it and it should work. Some older kernels had a bug causing this. In that case, run emerge x86info, update your kernel as asked and check the current frequency with x86info -mhz.

Q: I can change the CPU frequency, but the range is not as wide as in another OS.

A: You can combine frequency scaling with ACPI throttling to get a lower minimum frequency. Notice that throttling doesn't save much energy and is mainly used for thermal management (keeping your laptop cool and quiet). You can read the current throttling state with cat /proc/acpi/processor/CPU/throttling and change it with echo -n "0:x" > /proc/acpi/processor/CPU/limit, where x is one of the Tx states listed in /proc/acpi/processor/CPU/throttling.

Q: When configuring the kernel, powersave, performance and userspace governors show up, but that ondemand thing is missing. Where do I get it?

A: The ondemand governor is only included in recent kernel sources. Try updating them.

Q: Battery life time seems to be worse than before.

A: Check your BIOS settings. Maybe you forgot to re-enable some of the settings.

Q: My battery is charged, but KDE reports there would be 0% left and immediately shuts down.

A: Check that battery support is compiled into your kernel. If you use it as a module, make sure the module is loaded.

Q: I have a Dell Inspiron 51XX and I don't get any ACPI events.

A: This seems to be a kernel bug. Read on here.

Q: I just bought a brand new battery, but it only lasts for some minutes! What am I doing wrong?

A: First follow your manufacturer's advice on how to charge the battery correctly.

Q: The above didn't help. What should I do then?

A: Some batteries sold as "new" are in fact old ones. Try the following:

$ grep capacity /proc/acpi/battery/BAT0/info
design capacity:     47520 mWh
last full capacity:  41830 mWh

If the "last full capacity" differs significantly from the design capacity, your battery is probably broken. Try to claim your warranty.

Q: My problem is not listed above. Where should I go next?

A: Don't fear to contact me, Dennis Nienhüser, directly.