ASUS ROG G752VL Backlight Keys not working

Hello Zorin Forum,

I recently bought Zorin OS 12 Ultimate and I'm happy to say it is the best OS I've used yet. Although there is one issue, I cannot adjust the screen brightness using the FN + F5/6 keyboard shortcuts. Also, the brightness dial which can be seen by clicking on the power menu at the lower right hand screen of the task bar moves, but does not adjust the brightness at all. I have tried several fixes such as editing the etc/default/grub file and changing the GRUB_CMDLINE_LINUX_DEFAULT line to read GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_osi=" with no success. I also followed a tutorial detailed here: https://lajackson2.wordpress.com/2014/0 ... rightness/ but that actually made matters worse. Before following that tutorial I was able to use the xbacklight terminal application to change the backlight but that no longer works (although an ideal situation would be able to not have to use xbacklight and just use the keyboard shortcuts, hence why I'm posting). I'm using an ASUS ROG G752VL laptop which uses an NVIDIA GeForce GTX 950M graphics card. It is worth mentioning that I attempted to upgrade to the latest stable Linux Kernel (4.9.8) from the default installed kernel of 4.4.0-62 at fresh installation, therefore using the XORG drivers instead, but as soon as I installed the NVIDIA proprietary drivers, the system crashed and hung at non graphic log in script at boot up, forcing me to reinstall the system. In any case, I noticed that with NVIDIA or XORG the backlight keys simply did not work. I also sent a message to support through the premium support and they have yet to email me back. Any help would be greatly appreciated. Thank you in advance.

Hi, there is a very long thread here which mentions the fix you have tried without success but there is another one further down:

http://askubuntu.com/questions/762764/c ... -16-04-lts


"Pre Ubuntu LTS 16.04

Under (X)Ubuntu 14.04 LTS, brightness control on my Panasonic Toughbook CF-52 used to work fine by adding acpi_osi=Linux to the GRUB_CMDLINE_LINUX_DEFAULT= line in /etc/default/grub:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_osi=Linux"
and issuing

$ sudo update-grub
after editing and before rebooting.

Since Ubuntu LTS 16.04

However, above solution stopped working after upgrading to (X)Ubuntu LTS 16.04. This appears to be typical for laptops with integrated Intel video graphics.

One can check this with the following command:

$ ls /sys/class/backlight/
intel_backlight panasonic
At least intel_backlight should be mentioned, most probably in addition to an OEM name like for example panasonic, dell_backlight, etc.

If this is the case, proceed with creating the following file

$ sudo nano /usr/share/X11/xorg.conf.d/20-intel.conf
with contents:

Section "Device"
Identifier "card0"
Driver "intel"
Option "Backlight" "intel_backlight"
BusID "PCI:0:2:0"
EndSection
Reboot, and enjoy your backlight buttons!

Source

shareimprove this answer
edited Dec 11 '16 at 15:33
answered Dec 11 '16 at 15:27

Gin Gordon
1,1921125"

Also the hardware vendors don't want you to run GNU/Linux more than ever due to an increasing number of 'hybrid' graphics (Intel/nVidia) - which is what star treker has discovered to his cost. So before people start screaming at the OS, lobby the hardware vendors that there hardware sucks bigtime!

Thanks for the response, unfortunately when I execute the ls /sys/class/backlight/ command I am not presented with a string detailing an intel card, but rather, two cards labeled acpi_video0 and acpi_video1. So I don't think it will work since no intel card is displayed.

Hi, anything here help?:

http://askubuntu.com/questions/768959/u ... e-gtx-960m

The proprietary driver for my graphics card is enabled, the NVIDIA 367.57 driver. What is interesting though is that there is another option to select a driver for another device or card. The card/whatever it is, is listed as Unknown, and the driver options are to either use "using processor microcode firmware for intel CPUs from Intel Microcode (proprietary)" or do not use this device. I have the proprietary driver selected now although the card is still listed as unknown. I wouldn't think that would have to do with this backlight issue but maybe? Also, I've tried just about every and all possible fix for the whole Grub default thing and no success. However, I currently have it set to: GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_osi=linux acpi_backlight=vendor". When using the command ls sys/class/backlight the output changes from the previous acpi_video0 and acpi_video1 to asus-nb-wmi. For all of the sort, I also ran the command acpi_listen to check any output of hitting the fn + F5/6 keys but no output at all. Not sure if this furthers progress but it is additional information nonetheless. I really hope we can find a solution. This is linux after all so i'm hopeful.

IS the graphics functioning with the exception of the back light issue?

yeah aside from the backlight keys not working everything works just fine.

Can you see if the solution posted here helps? (And yes I am aware the post relates to pre-16.04!) :

https://ubuntuforums.org/showthread.php ... st12843462

The bad news is that it didn't work, the good news is that I have more info to help out. So first off I changed my default grub file to GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_osi=\"!Windows 2012\"". Rebooted. Then I executed the ls /sys/class/backlight command and I got the output of the previously mentioned acpi_video0 and acpi_video1. I noticed from a lot of other posts I looked up that many people had their actual keyboard backlight settings in acpi_video0. So since there was no intel backlight directory, I just replaced in my mind where the tutorial said "intel backlight" with "acpi_video0". I tried that echo command to read 0 to the brightness file since the max file read the max as 100 and the current was 10 (even though it looked a lot brighter than 10%). No changes, no success. However, when I checked the file through the file manager GUI and opened it to see if it changed, it did. In addition, I am attaching a picture to verify that what seems like the necessary scripts and such are already within the directory of acpi_video0. So, where all this is going. It seems like all the necessary scripts and stuff were already installed on the machine like they should be but for whatever reason, it isn't linking to the keys. I tried the "xev" command to check key responses. The fn 10/11/12 keys which control audio adjustment respond just fine, which I already knew and have seen, but no other fn key combo registers. I also tried the acpi_listen command and discovered the same findings, only the audio fn key shortcuts work. Also, another oddity, before whenever I had acpi_osi in the script for the etc default grub file I couldn't get xbacklight to work. But now, it works. Once again, yay for changing backlight through any means but the whole purpose of this post is because the shortcut keys don't work. But it is a variable nonetheless. So, hopefully this new info helps move further to a possible solution.

Hi and thanks for the feedback - I don't think I can progress this any further as I am no coder and I don't have a modern notebooke like you do. Here's hoping a solution can be found soon. I am happy to keep this thread open unless you state otherwise.

Thanks I'll try to keep progressing and post progress if I find it. Hopefully premium support will get back to me at some point soon. I didn't spend 21 dollars on nothing I hope.