Episode #125 of the Stack Overflow podcast is here. We talk Tilde Club and mechanical keyboards. Listen now
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Arch Linux has the following to say about xbacklight: Brightness can be set using the xorg-xbacklight package. Note: xbacklight only works with intel. Radeon does not support the RandR backlight property. xbacklight currently does not work with the modesetting driver. To set brightness to 50% of maximum: $ xbacklight -set 50 ...


5

I dug around a bit, and the reason behind your "LCD cooler" turned out to be incredibly interesting, in my opinion: First off all, apparently LCD devices being listed as coolers under acpi are a thing, and not just a strange feature of your laptop - there are some more examples of those floating around online. If you do acpi -c yourself, you can list your ...


5

xbacklight $ xbacklight +30% # increases brightness by 30 percent $ xbacklight -30% # decreases brightness by 30 percent dbus way $ dbus-send --session --print-reply \ --dest="org.gnome.SettingsDaemon" \ /org/gnome/SettingsDaemon/Power \ org.gnome.SettingsDaemon.Power.Screen.SetPercentage \ uint32:<percentage> Example Set ...


5

Just managed to control my screen brightness in Debian with xrandr. xrandr --output [your display] --brightness 0.8 You can find your display name by typing xrandr - you'll see it as something like "[your display] connected primary 1920x1080..." Next up... key bindings!


4

Giorgos Keramidas wrote a script that relies in dbus and UPower - which most desktop distros have up and running. I would recommend using this instead of scripts that write to /sys/class/... as they need to be run as root - either through sudo or a by having SUID set - and that is bad security practice. Basic usage is as simple as kbdbacklight up ...


4

This is an old question, but an answer may help out others. I ran into an issue upon a fresh installation of i3wm on my laptop where, for whatever reason, my XF86MonBrightnessUp/Down keys weren't being registered (I checked with xev). What I ended up doing is creating acpi actions and events which corresponded to the keys being pressed. The following are ...


3

Display and brightness settings not working anymore is a bug introduced by a bad transition of GNOME (3.20 -> 3.21) from sid to testing. The bug will fix itself once the transition is complete. If you cannot wait for a couple of days, consider upgrading the packages which are still on 3.20 (upgrading the package mutter fixed the problem for some people). ...


3

You can give yourself the permission to write to /sys/class/backlight/*, or add a sudo rule to modify the file. That's what I did when I had a computer with an i915 GPU. For example, add something like the following code to /etc/rc.local: chgrp -R backlighters /sys/class/backlight chmod g+w /sys/class/backlight/*/* and add yourself to the backlighters ...


3

Unfortunately I was never able to get the function keys to lower the screen brightness. Solution: Get nux-desktop for centos 7 repo Install xbacklight (testing xbacklight -10 and xbacklight +10 to validate it was going to work after install). Disabled nux-desktop in yum Setup keyboard shortcuts to lower/increase screen brightness. For some reason the '...


3

There are many ways to do this, but since it seems that your graphics card is made by Nvidia, I think the way which works best is the following (assuming you use nvidia-driver): Create a file called 10-brightness.conf to /etc/X11/xorg.conf.d/ Write the following lines to the file you just created: Section "Device" Identifier "Device0" Driver ...


3

During operating system boot, the OS obtains various ACPI tables from the BIOS and interprets the "tables", which really look more like program code. One quite popular table is the DSDT, but it's not alone. The ACPI tables are created in the form of textual source code (see the example linked above), and are compiled into binary form using a tool called ...


2

The issue was a missing driver. After being in contact with advantech they had drivers built for both 32 and 64 bit Ubuntu which were not on their website. The Ubuntu drivers (of the correct architecture) work on Debian enabling brightness control.


2

I've found the solution. I had to create two files in xorg.conf.d directory. 60-monitor.conf, and 60-screen.conf. Then I generated a xorg.conf file with the nvidia driver (nvidia-xconfig). I copied the monitor section into the 60-monitor.conf file, and the screen section to the 60-screen.conf file. Plus I added the plus two lines, which were mentioned above.


2

Use light: bindsym XF86KbdBrightnessUp exec light -k -A 10 bindsym XF86KbdBrightnessDown exec light -k -U 10 It is available in a packaged version for Arch and Fedora at the moment. But you can always build if from source easily. Find the git repository here: https://github.com/haikarainen/light .


2

There are quite a few questions about "brightness keys don't work", and the usual debugging method applies: Find out with evtest and xev if the brightness keys produce the correct keysyms Find out how to actually change the backlight intensity. If /sys/class/backlight/... doesn't work, but xbacklight (which uses xrandr) does, I'd stick with xbacklight. So ...


2

There can be numerous reason why this doesn't work, and they are all to complicated to ask in a comment to the question, so I'll leave this as a resource here - and if none of these work feel free to comment rather than down-voting and I'll remove it (or leave for others who end up here with the same problem but different causes). The first thing you can ...


2

The backlight is set by gsd-backlight-helper, a gnome-settings-daemon helper which runs as root, thanks to a PolicyKit setting allowing the active user to do so. /usr/share/polkit-1/actions/org.gnome.settings-daemon.plugins.power.policy contains the following: [...] <action id="org.gnome.settings-daemon.plugins.power.backlight-helper"> [...] <...


2

You could install the xset package and try: xset dpms force off And if that does not work, maybe yet before it: xset +dpms


1

You can do it with ddcutil, as mentioned here, but it's not that responsive and requires root privileges: # ddcutil capabilities | grep Brightness Feature: 10 (Brightness) # ddcutil getvcp 10 VCP code 0x10 (Brightness ): current value = 60, max value = 100 # ddcutil setvcp 10 70 I don't think that there's "one size fits all" ...


1

Edit the file /etc/default/grub and add the below parameters to the GRUB_CMDLINE_LINUX_DEFAULT: $ sudo nano /etc/default/grub GRUB_CMDLINE_LINUX_DEFAULT="quiet acpi_osi=Linux acpi_backlight=vendor" Do not forget to run sudo update-grub afterwards.


1

The Fn keyboard combinations work differently on every laptop. Brief overview: When you press these combinations, some laptops produce keyboard events, some laptop produce ACPI events. The Linux kernel interprets these, and makes them available on a /dev/input/event* device. X reads those and converts them into X keyboard events. An application, typically ...


1

I struggled with brightness on Dell L702X with Nvidia GT550M. You can see what I've found in this thread (link). Maybe some of those things will work for you. I wasn't able to use xbacklight(1) (or activate the brightness control keys) but I've found a couple of other ways to change the brightness: xrandr(1) Thanks to this post (link) I was able to change ...


1

This Happened to me too. If you take a notice, that version of gnome is supposed to be for sid, not testing. Go and open terminal and you will see gnome-shell --version outputs the right version for testing. This is a version mismatch thus you can call it simply a weird bug. Update gnome-shell from sid repository. Just add deb http://ftp.us.debian.org/...


1

As suggested in the comments, I used the graphics card and driver information, obtained via lshw -c video, to narrow my search. $ls /sys/class/backlight/ ideapad intel_backlight Using ideapad, which seemed to be the system default, had no effect, but using intel_backlight did: $echo 1000 | sudo tee /sys/class/backlight/intel_backlight/brightness 1000 I ...


1

I installed the precompiled 4.3.0-0.bpo.1-amd64 kernel following this guide, and immediately an entry intel_backlight appeared in /sys/class/backlight, and the program xbacklight worked, too. (It seems like the hardware was so new that it was not supported by the old kernel. I just got this notebook.) Now, I am kind of excited that this works, since it was ...


1

You could write your own pretty easily. Create two shell scripts containing the echo lines above somewhere in your path (/usr/local is the normal place). Set the permissions 755 owned by root. Then either edit your sudoers file to allow them to be run as root, or use chmod +s to set them SUID. This sort of thing is considered a security risk, BTW, so ...


1

acpi_osi= causes Linux to disable the ACPI Operating System Identification function (_OSI) when executing ACPI code provided by the mainboard. Your laptop probably checks for specific Windows versions to switch between different modes of how the brightness hotkeys are reported to the OS. Linux usually presents itself as a recent Windows version to ACPI code,...


1

Confirmed Gnome Bug Why hello there 2015, here's 2017 and we've got Debian 9 Stretch as the stable branch. So just upgrade Gnome was the answer you were looking for. I am currently using the exact same setup but with Gnome 3.22.2, and it works great.


1

In the realm of laptops with Intel chipsets, there seems to be a division between the LVDS- and eDP-connected panels: eDP: echo 4 > /sys/class/backlight/intel_backlight/bl_power …should turn off the backlight. echo 0 > /sys/class/backlight/intel_backlight/bl_power …should turn it on again. LVDS: I have discovered that it is not possible to turn ...


1

From X Windows From X Windows you can use the application xbacklight to get and set the percent brightness for your screen. Example current level $ xbacklight -get 100.000000 set to 75% $ xbacklight -set 75 $ xbacklight -get 73.333333 set back to 100% $ xbacklight -set 100 $ xbacklight -get 100.000000 From the console To achieve something similar ...


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