Ubuntu 18.04 external full HD monitor flicker
Finally a simple change of resolution from 1920 x 1080i to 1920 x 1080 (at Settings - Devices - Displays - [choose the problematic display] Resolution) worked.
Just putting it out there if someone ever stumbled upon this problem.
I've similar problems with my monitor&Ubuntu18(laptop). After some investigation, I fixed this problem and found the root cause in my environment.
My problem's root cause is in the HDMI signal quality, and the HDMI signal poor quality has two root causes:
- The HDMI cable;
- The HDMI cable doesn't plug into the socket closely;
My final solutions are as:
- Re-plugin the cable with your PC and monitor, and secure them carefully;
- Buy and use a new high-end HDMI cable(above 20$, seller should claim it support 4K or 8K);
- If you couldn't do the 2nd solution, and the problem still exists, lower your display configuration just like the solutions provided by others in this issue, e.g. lower the display resolution to 720P, or lower the display frequency. These lower resultion doesn't require high signal quality transferring capability in your cable, so they could work without problem.
I had this problem with a Samsung curve screen external monitor on Ubuntu 18.04.3 LTS
To solve it I tried with different resolution aspect ratio. Specifically it was 16:9 for external and I changed it to 16:10. After that, it worked fine, and no need to restart the machine in my case.