brillo(1)

Cameron Nemo OCTOBER 2018

NAME
brillo - control the brightness of backlight and keyboard LED devices

SYNOPSIS
brillo [operation [value]] [-k] [-q|-r] [-m|-c] [-e|-s ctrl] [-u usecs] [-v loglevel]

DESCRIPTION
brillo is a tool for controlling the brightness of backlight and LED devices on Linux. Notable features include:

•   Automatic best controller detection

•   Smooth transitions and exponential (natural) adjustments

•   Ability to save and restore brightness across boots

•   Directly using sysfs to set brightness without relying on X

•   Unprivileged access with no new setuid binaries

•   Containment with AppArmor

OPTIONS
Operations

•
    -G:    Get brightness value (default)

•
    -S VALUE:    Set brightness to value

•
    -A VALUE:    Increment brightness by given value

•
    -U VALUE:    Decrement brightness by given value

•
    -O:    Store the current brightness

•
    -I:    Restore cached brightness

•
    -L:    List available devices

•
    -H:    Show a short help output

•
    -V:    Report the version

Controllers

The default controller is automatically selected to maximize precision. To select every controller available, use the -e option. To select a specific controller, use the -s option.

•
    -a:    Automatic controller selection (default)

•
    -e:    Operate on every controller available

•
    -s CONTROLLER:    Manual controller selection

The list operation (-L) can be used to discover available controllers.

Targets

By default, brillo acts on the display devices, but the -k option can be used to adjust keyboard backlights instead. In either case, it may be necessary to specify an alternative controller.

•
    -l:    Act on display backlight (default)

•
    -k:    Act on keyboard backlight and LEDs

Fields

By default, brillo acts on the brightness property. With these options, the maximum brightness of a controller can be retrieved. In addition, it is possible to set (or retrieve) a minimum cap, which is used to prevent lowering the brightness beyond a certain threshold. This is especially useful for devices that become pitch black when the brightness is set to 0.

•
    -b:    Current brightness (default)

•
    -m:    Maximum brightness

•
    -c:    Minimum brightness

Value modes

Values may be given, or presented, in percent or raw mode.

The default value mode is linear percentages, however the -q option can be used for exponential percentages. Exponential mode offers a more natural and gradual brightness scale.

Raw mode will use the same format and range given by the device driver; this mode is most useful when a high degree of precision is required, such as for keyboard controllers.

•
    -p:    Linear percentages (default)

•
    -q:    Exponential percentages

•
    -r:    Raw values

Smooth adjustment

brillo is capable of gradually adjusting the brightness over a specified time period. Use the -u microseconds option to specify how long the operation should take. This flag is silently ignored when not setting the brightness.

•
    -u microseconds:    time used to space the operation out

Verbosity

By default, brillo outputs only warnings or more severe messages. To enable more verbose logs on stderr, use the verbosity argument: -v loglevel. The loglevel is a value between 0 and 8 (corresponding to syslog severities).

EXAMPLES
Get the current brightness in percent:
    brillo [-G]

Increase brightness by 5 percent:
    brillo -A 5

Specify the controller to use:
    brillo -s intel_backlight -A 5

Set the brightness to 50% for every controller:
    brillo -e -S 50

Retrieve or increase the brightness using an exponential scale:
    brillo -q
    brillo -q -A 5

Decrease the brightness and smooth the operation over 1500 microseconds:
    brillo -u 150000 -U 5

Get the raw maximum brightness value:
    brillo -rm

Set the minimum cap for the acpi_video0 controller to a raw value of 2:
    brillo -rc -s acpi_video0 -S 2

Note: subsequent attempts to set the controller's brightness to a raw value less than 2 will then be raised to this minimum threshold.

List keyboard controllers:
    brillo -Lk

Activate a specific controller LED:
    brillo -k -s "input15::scrolllock" -S 100

Note: LEDs often only take 0 or 1 in raw value (i.e. for off/on). In these cases, you can use any non-zero value instead of 100.

COPYRIGHT
Copyright (C) 2018-2019 Cameron Nemo, 2014 Fredrik Haikarainen

This is free software, see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE