for the watts

dependencies

• bash
• udev
• hdparm
• iw

configuration

The config file is located at /etc/conf.d/ftw.

universal options

STATE_FILE

• File to which the state (adp or bat) will be written after the respective custom function (see below) is called.

MODULES

• Array of modules to be removed when offline and inserted when online.

PARTITIONS

• Device partitions affected by REMOUNT_OPTIONS.

DEVICES

• Devices affected by BLOCKDEV_READAHEAD, HD_POWER_MANAGEMENT, and HD_SPINDOWN_TIMEOUT.

state-dependent options

CPUFREQ_GOVERNOR

• CPU power scheme governor.

NMI_WATCHDOG

• Execute periodic NMI interrupts to monitor CPU lock ups?

BUS_CONTROL

• Control everything in /sys/bus/*/devices/*.
• on means device should be resumed and autosuspend is not allowed.
• auto means device is allowed to autosuspend and autoresume.

USB_AUTOSUSPEND_TIMEOUT

• How long to wait before suspending USB devices.

PCIE_ASPM_POLICY

• PCI Express Active State Power Management.
• Will probably require pcie_aspm=force kernel boot parameter.

LAPTOP_MODE

• Attempt to maximize the amount of time disks spend in a low power state by submitting all future pending disk IO when performing an IO operation?

DIRTY_RATIO

• Maximum percentage of memory dirty pages can occupy before processes are forced to write dirty buffers themselves.

DIRTY_BACKGROUND_RATIO

• Maximum percentage of memory dirty pages can occupy before pdflush begins to write them.

DIRTY_EXPIRE_CENTISECS

• How long data can be in the page cache before it expires, signifying it must be written at the next opportunity.

DIRTY_WRITEBACK_CENTISECS

• How often pdflush wakes up to write data to disk.

SCSI_HOST_POLICY

• Policy for SCSI host adapters.

REMOUNT_OPTIONS

• Comma-separated list (option1,option2,etc) of mount options to be applied when remounting devices.

BLOCKDEV_READAHEAD

• Block device readahead in kilobytes.

HD_POWER_MANAGEMENT

• Hard drive Advanced Power Management.
• See hdparm(8) (-B flag section) for more information.

HD_SPINDOWN_TIMEOUT

• How long to wait after disk activity stops before turning off hard drive's spindle motor.
• See hdparm(8) (-S flag section) for more information.

SND_INTEL_POWER_SAVE

• Enable Intel HDA audio chipset power saving?

SND_AC97_POWER_SAVE

• Enable AC97 audio chipset power saving?

WIRELESS_POWER_SAVE

• Enable wireless adapter power saving?

BACKLIGHT_BRIGHTNESS

• Dim backlight to save power?
• For max value (min is 0), check /sys/class/backlight/acpi_video*/max_brightness.

custom functions

The custom-adp or custom-bat function is called upon a change in state, before the state file is updated.

examples

Disable Wake-on-LAN on battery with ethtool:

custom-bat() {
    ethtool -s eth0 wol d
}

custom-adp() {
    ethtool -s eth0 wol g
}

Manage backlight brightness per state using relight:

custom-bat() {
    if [[ -f $STATE_FILE && $(< $STATE_FILE) == 'adp' ]]; then
        relight save adp
        relight restore bat
    fi
}

custom-adp() {
    if [[ -f $STATE_FILE && $(< $STATE_FILE) == 'bat' ]]; then
        relight save bat
        relight restore adp
    fi
}