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How to control laptop LCD screen backlight? (Solved, plus)

Posted: Wed 27 Sep 2006, 03:32
by giiba
So, I've spent much time over the last two weeks (30+ hours) trying to get puppy to control the LCB backlight of my laptop screen. It is currently at max brightness and there is nothing I can figure to do. I have:

-added modules: LCD, backlight, video
-compiled and installed hotkeys and acpid as per instructions here: http://www.da-cha.org/letsnote/
-compiled and installed pcc_acpi module (same link)
-installed updated Berkeley DB (3.2.9) to support hotkeys

all of this compiles and runs fine, just nothing happens to my screen brightness.

Has anyone else been able to alter the screen brightness on their laptop? I do not necessarily need to have my hotkeys working, but running at full brightness dramatically reduces my battery life. Also, when I leave my lid open, puppy will blank the screen but it is obvious that the backlight is still on. I'm a linux newbie so I could be over-looking something simple. Please help. I'm running puppyoffice 2.02.

Posted: Wed 27 Sep 2006, 16:20
by giiba
I solved my problem... it turns out that in my haste I copied the 'template' files over the real files in /etc/acpi. Once I reloaded the actual script, surprise, everything works. Even things I wasn't expecting to have work; my sound is now working, hoorah!

I had given up on the sound system, figuring that it was some weird bug that prevented it from working. However upon messing around in the /proc/acpi/pcc, the speaker "clicked" as I toggled the mute function. To my joy when I loaded http://www.weebls-stuff.com/toons/kenya/ (my favorite test for computer functioning) I was greeted by full sound for the first time in linux. After digging around in the scripts, I found the configuration area and now all is working.... and what's this? My laptop never sounded this good. Under Windows XP the sound was crackly at med-high volumes... under linux the sound is clear and very good until very high volumes.

the conlusion: Linux sounds better :lol:

Posted: Sat 03 Aug 2013, 12:40
by meckelman
Brightness backlight control For Precise 5.7 on a laptop.

Code: Select all

xrandr --output LVDS --brightness .7
I guess .7 ~= 70% brightness.
Just run xrandr solo to see the output devices you can control.
xbacklight didn't work. It worked on Precise 5.6, but not 5.7.1.

Posted: Mon 16 Mar 2015, 21:59
by fm1st
As this is a similar thread, for anyone who still need a solution to control screen brightness in a laptop which, for any reason, does not have its brightness keys working, see CADEJO’s post at:
http://murga-linux.com/puppy/viewtopic.php?t=87873
It essentially builds a pop-up menu at the TASKBAR to control brightness in JWM. I followed his brilliant workaround and managed to put back in good use a "sick" but still very powerful laptop (Sony VAIO, with Intel Core2 Duo P9500 @2.53Gh, 4 Gb Ram), which due to some spanking by previous owner (probably due to its OS (Ruindows) in a broken HD), its whole keyboard, touch-pad and all function keys, all went completely dead broken, with the screen locked at its highest possible brightness, causing lots of eye strain.