Gamma slider does not work

[benit]

Can anybody reproduce this? I have switched to NVidia recommended drivers. I have a card with NVidia Optimus, GT 645.

[AJSlye]

Nvidia Optimus means that you have both an Intel chip, as well as the Nvidia chip.
Typically the Intel is used for day to day computing, while the nvidia is reserved for gaming (3D graphics).

You can use bumblebee, like you would on all other distributions:
https://wiki.ubuntu.com/Bumblebee

Or you can use Ubuntu's Nvidia prime utility:
http://askubuntu.com/questions/412452/ge...ime-gt650m

[benit]

I meant that the Gamma correction slider in system settings does not work. Also not with maui 17.06. Both Nouveau driver as well as NVidia drivers fail.

What is going on?

[leszek]

In general this should work. There are different modes like greyscale and RGB and such. I tested the greyscale sliders and that work just fine.
Have you maybe forget to hit Apply? Or doesn't it change at all when sliding around?

[benit]

It does not change at all when sliding around.

[leszek]

What about the command xgamma -gamma 2.0? Does this work for you?

[benit]

Code:

$ xgamma -gamma 2.0
-> Red  1.000, Green  1.000, Blue  1.000
<- Red  2.000, Green  2.000, Blue  2.000

The numbers change, but not the screen gamma, nothing visible happens

[leszek]

Very strange then.
If you have the proprietary nvidia driver installed it might be best to try changing the gamma setting with the nvidia provided tools.
Nvidia-xsettings it is called as far as I am aware.

[benit]

the command "nvidia" does not exist (on my notebook) !?

[leszek]

There is no command nvidia that is correct.
The nvidia configuration tool is called nvidia-settings.