Asus UX51VZH - Changing values to the files in nvidia_backlight does nothing

[AM2petterk]

I have been struggling with backlight control on this laptop since day 1.

Tried all sorts of kernel commands through bootloader, like "acpi_backlight=vendor" + "acpi_osi= " and acpi_osi="!Windows 2012" etc

Most of the time, I have a acpi_video0 directory in /sys/class/backlight, but chaning the brightness values etc does nothing.

In one instance, I think it was with the "!Windows 2012" command, I had two directories in /sys/class/backlight. The other was "nv_backlight" or something like that, and changing the values of "brightness" inside that directory also changed the backlight brightness correctly, but with this acpi_command at the kernel line, none of my brightness keys were working.

SO I installed the nvidiabl-module and the nvidiablctl from AUR (Arch), loaded the module, and a new directory was created, but nothing happens to the backlight when I change the values of "brightness" or use the nvidiablctl.

[code]lspci | grep VGA 01:00.0 VGA compatible controller: NVIDIA Corporation GK107M [GeForce GT 650M](rev a1) [/code]

This is a UX51VZH or U500 as its called in Europe, with the WQHD+ display, plain NVIDIA graphics (not optimus, just this gt650m) and corei7 cpu.

[AM2petterk]

UPDATE:

After reading abit, and trying out "modprobe nvidiabl screen_type=3" it now works when I echo values to the brightness file!

Yay!

However, how can I get rid of the acpi_video0 directory (or asus-nb-wmi, depends on what kernel options I pass in the bootloader)? The brightness keys dont control the nvidia_backlight directory, only the other one.

[AM2petterk]

Im closing this issue.

For those of you that may have been struggling with the Asus UX51VZH/U500VZ, this is how I worked it out:

• Install the proprietary nvidia drivers
• Append "acpi_osi=Linux" to your kernel line in the bootloader (I use refind-efi)
• Install nvidiabl (current version Im using is 0.87-3 from AUR)
• I use cinnamon, and I figured out how to integrate it with the OSD through Dconf. Go to Dconf Editor. Press Ctrl-F, type "backlight". The options should appear right away.

Enable "backlight helper force", and set the "backlight-helper-preference-order" to "raw, firmware, platform".

On this laptop, I had to configure the max and min settings through nvidiabl.conf in /etc/modprobe.d/

this is the content of that file: " options nvidiabl max=0x19000 min=50 off=0 screen_type=3 "

To autoload the module at boot:

touch /etc/modules-load.d/nvidiabl.conf

nano /etc/modules-load.d/nvidiabl.conf

Insert "nvidiabl" into that file.

Reboot, and you should be fine. In my experience, the backlight saves through suspend/resume, atleast in Cinnamon.