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How to lower brightness in Linux to eliminate whining?

Posted: Sat Mar 30, 2019 11:17 am
by resistante
I've read https://www.silentpcreview.com/stop_lcd_whine

It works for my monitor, but it's too bright. How can I lower brightness in Linux? I use Intel integrated graphics.

Re: How to lower brightness in Linux to eliminate whining?

Posted: Mon Apr 01, 2019 4:32 am
by edh
Depends upon your distro but Arch has a fairly thorough Wiki page as always:
https://wiki.archlinux.org/index.php/backlight

It refers to a tool called xorg-xbacklight which can be run from the shell amongst other places:

Code: Select all

$ xbacklight -set 50

Re: How to lower brightness in Linux to eliminate whining?

Posted: Mon Apr 01, 2019 11:25 am
by resistante
Any idea how to do this on Debian 9 with GNOME?

There's nothing in /sys/class/backlight. There's no xorg.conf or xorg.conf.d in /etc/X11. Doing xbacklight -set 50 does nothing. Same if I put

Code: Select all

Section "Device"
    Identifier  "Intel Graphics" 
    Driver      "intel"
    Option      "Backlight"  "intel_backlight"
EndSection
in /etc/X11/xorg.conf.

GNOME commands from https://wiki.archlinux.org/index.php/ba ... with_Gnome report these errors:

Error: GDBus.Error:org.gtk.GDBus.UnmappedGError.Quark._gsd_5fpower_5fmanager_5ferror.Code0: gsd-backlight-helper failed: Could not get or set the value of the backlight: No backlight devices present

and

Error: GDBus.Error:org.gtk.GDBus.UnmappedGError.Quark._gsd_5fpower_5fmanager_5ferror.Code0: Screen backlight not available

xcalib -co 40 -a results with Error - unsupported ramp size 0

I'm using an Ivy Bridge i3 and may be moving to Coffee Lake i3 soon.

Re: How to lower brightness in Linux to eliminate whining?

Posted: Tue Apr 02, 2019 4:51 am
by Klusu
Power draw does not bother you.
You want to adjust brightness. Not backlight.
https://www.ostechnix.com/how-to-adjust ... -in-linux/

Re: How to lower brightness in Linux to eliminate whining?

Posted: Tue Apr 02, 2019 6:32 am
by resistante
Klusu, this works pretty well, although it changes colors somewhat which isn't ideal and also completely doesn't cooperate with redshift (blue light reducer) which disables the brightness change every 5 seconds, if I run it in infinite loop it will just flash bright light at me every 5 seconds.

I wonder if that xbacklight thing wouldn't happen to be a better tool for this. I think this should be directly controled by GPU, so that the colors are right.

Re: How to lower brightness in Linux to eliminate whining?

Posted: Tue Apr 02, 2019 11:54 pm
by Klusu
It seems you WANT to adjust the backlight. You can't. The monitor does not have the hardware for that. The directory sys/class/backlight is empty because Linux has found nothing it could put in there. Even if you could, you would get the same whine.

Re: How to lower brightness in Linux to eliminate whining?

Posted: Wed Apr 03, 2019 1:32 am
by Vicotnik
I don't know how to do it with Intel, maybe xrandr or xbrightness/xbrightness-gui ?

http://shallowsky.com/blog/linux/x-brig ... randr.html
http://shallowsky.com/blog/linux/bright ... -in-x.html