Arch Linux

Reasons

Member

From: Washington

Registered: 2007-11-04

Posts: 572

Screen backlight

I can successfully change how bright the screen is with the command

echo 80 > /sys/class/backlight/acpi_video0/brightness

I would like to have that exectued when I unplug the power cord so I install laptop-mode and changed the settings to as follows:

# LCD brightness settings
# -----------------------
#
# Using these settings, you can make laptop mode tools automatically adjust
# your LCD's brightness settings. The settings are extremely simple -- they
# only allow for the execution of a command, nothing more. The reason for this
# is that LCD brightness settings are very different between laptop vendors.
#
# Suggestions for commands:
#
#  * If your system has the file "/proc/acpi/video/VID/LCD/brightness" (VID may
#    be VID1 or similar), use this file as BRIGHTNESS_OUTPUT, and use
#    the command "echo <value>". The possible values can be listed using the
#    command:
#
#       cat /proc/acpi/video/VID/LCD/brightness
#
#  * If you have a file /sys/class/backlight/.../brightness, then you can use
#    that file as BRIGHTNESS_OUTPUT, and the command "echo <value>".
#
#    As far as I understand it the values are between 0 and
#    the value contained in the file /sys/class/backlight/.../max_brightness.
#
#  * For Toshiba laptops, use the command "toshset" with the -lcd or -inten
#    command. Read the toshset(1) manual page for more information on the
#    parameters for this command. If you use this command, set
#    BRIGHTNESS_OUTPUT to "/dev/null".
#
###############################################################################


#
# Should laptop mode tools control LCD brightness?
#
CONTROL_BRIGHTNESS=1


#
# Commands to execute to set the brightness on your LCD
#
BATT_BRIGHTNESS_COMMAND="echo > 50"
LM_AC_BRIGHTNESS_COMMAND="echo > 80"
NOLM_AC_BRIGHTNESS_COMMAND="echo > 80"
BRIGHTNESS_OUTPUT="/sys/class/backlight/acpi_video0/brightnes"

and

 /etc/rc.d/laptop-mode start

goes just fine. But when I run "laptop_mode start" I get

Laptop mode enabled, active.
/usr/sbin/laptop_mode: line 1538: /sys/class/backlight/acpi_video0/brightnes: Permission denied

nogoma

Member

From: Cranston, RI

Registered: 2006-03-01

Posts: 217

Re: Screen backlight

Looks like maybe you just have a typo? "brightnes" v. "brightness"?

---

-nogoma
---
Code Happy, Code Ruby!
http://www.last.fm/user/nogoma/

Reasons

Member

From: Washington

Registered: 2007-11-04

Posts: 572

Re: Screen backlight

I noticed that right after. Even then though, everything runs fine but nothing happens when I unplug the AC cord. If I type in "laptop_mode auto", it changes, but it should be doing that on it's own.