This message was posted on behalf of Intel Corporation
I understand you are trying to adjust Contrast setting on Ubuntu* Linux*.
Let me apologize for any inconvenience this issue may be causing to you.
What happens is that support for Linux* operating systems is provide by the Linux* Community directly. I recommend contacting the Linux* Community so they can provide assistance about adjusting Contrast setting. This link will give you their contact information http://community.ubuntu.com/
This link will provide more information about Linux* support on Intel products https://www.intel.com/content/www/us/en/support/graphics-drivers/000005520.html