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Efo
Guru
Joined: 23 Jun 2005
Posts: 494
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 Posted: Sun Apr 02, 2017 4:32 pm Post subject: laptop brightness is max after reboot [SOLVED] |
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Hi all,
I cant figure out how to set a default value for the backlight of my laptop. The controls work, but every time I reboot the light is set to max.
gentoo wiki mentions
| Code: | | /etc/laptop-mode/conf.d/lcd-brightness.conf |
(which I think is where the default values are stored), but I dont have that file.
I guess what I am looking for is where to generate the conf file and then I will follow this syntax, but since I dont have the file that may be obsolete.
Any help is (as always) highly appreciated.
Thanks,
Efo
Last edited by Efo on Mon Apr 03, 2017 12:55 am; edited 1 time in total |
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cboldt
Veteran
Joined: 24 Aug 2005
Posts: 1046
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| Posted: Sun Apr 02, 2017 6:13 pm Post subject: |
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I don't use the "laptop-mode-tools", which might include the "missing config file" that you ask about.
If you have installed laptop-mode-tools, and the config file still isn't there, you would just create it.
The method I use to set LCD brightness at boot is a one line command in /etc/local.d/local.start
That file is not part of any package, but is suggested by openrc. More particularly, it is suggested by a message in /etc/init.d/local. If you don't use openrc to start your system (that is, if you use systemd), then this one liner in /etc/local.d/local.start would have NO effect.
I made /etc/local.d/local.start with a text editor. After I created the file, I made sure /etc/init.d/local was part of my openrc startup sequence, by issuing the command `rc-update add local default`
| Code: | # /etc/local.d/local.start:
# $Header: /home/cvsroot/gentoo-src/rc-scripts/etc/conf.d/local.start,v 1.4 2002/11/18 19:39:22
# This is a good place to load any misc.
# programs on startup ( 1>&2 )
# Adjust backlight brightness
echo 8 > /sys/class/backlight/acpi_video0/brightness |
Your computer and setup may use a different "/sys" file for this function, but I see reference to this location in the config file that you reviewed. |
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khayyam
Watchman
Joined: 07 Jun 2012
Posts: 6227
Location: Room 101
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| Posted: Mon Apr 03, 2017 12:48 am Post subject: |
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Efo ... as cboldt mentions, its somewhat dependent on what your backlight provides, but here is a script that (absent of any parameter) will set the brightness to half that of max_brightness (you could of course set the default to whatever value you want).
| Code: | #!/bin/sh
set -e
backlight_sys_dir="/sys/class/backlight/intel_backlight"
read -r max_brightness < "${backlight_sys_dir}/max_brightness"
read -r curr_brightness < "${backlight_sys_dir}/brightness"
if [ "$#" -eq 0 ] ; then
# set to half that of 'max_brightness'
echo $((max_brightness / 2)) > ${backlight_sys_dir}/brightness
exit 0
fi
case "$1" in
up) increment="+ 10" ;;
down) increment="- 10" ;;
*) exit 1 ;;
esac
new_brightness=$(($curr_brightness $increment))
if $((new_brightness < 1)) || $((new_brightness > $max_brightness)); then
exit 1
else
echo "$new_brightness" > ${backlight_sys_dir}/brightness
fi |
This could similarly used in /etc/local.d ... and you can also then call the script and pass 'up' and 'down' to adjust the brightness by plus/minus 10 (I call it via acpid with those parameters taken from 'brightnessup' and 'brightnessdown' keys).
HTH & best ... khay |
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Efo
Guru
Joined: 23 Jun 2005
Posts: 494
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| Posted: Mon Apr 03, 2017 12:54 am Post subject: |
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Hi cboldt and khayyam,
Thank you for the reply.
For some reason I was expecting to have some config file already present; however, your suggestions make a lot of sense: just a little scripting will do.
Thank you for your help.
Cheers,
Efo |
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