Ubuntu – Flickering screen with Radeon graphics on Ubuntu 18.04


I had Ubuntu 14.04.5 LTS running on

  • HP Compaq nx9420;
  • [AMD/ATI] RV530/M56-P [Mobility Radeon X1600]
  • screen resol.: 1680×1050 60.1*
  • kernel 3.13.0-161 and radeon.ko Version: 2.36.0

It was working without problems. Screen ok. No flickering.

Because support for 14.04.5 LTS will end next year, I tested Ubuntu 18.04.1 with kernel 4.15.0-36, radeon 2.50.0.

The screen starts flickering as soon as the radeon kernel module loads; flickering starts in text-mode (console) and continues when starting lxde graphics.

I tested several systems / kernels (Knoppix, Puppy, UBCD) and found
out that kernels using a radeon-driver <= 2.37.0 are OK and those
using radeon-driver >= 2.43.0 cause the flicker-problem.

How can I use radeon-driver 2.37.0 on Ubuntu 18.04.1?
or how can I avoid flickering screen with radeon-driver > 2.43.0?

You can see (short videos) what I'm talking about at:
flickConsole.mp4 # the flickering console in textmode
flickDesktop.mp4 # the flickering grafic dektop

I found a "kind of work-around" when the screen flickers:
use xrandr to switch modes (may be: multiple times)
(1) see the available modes: xrandr
(2) switch to e.g.:
xrandr –output LVDS –mode 1440×900
(3) wait some time; e.g. sleep 3
(4) switch back to the default mode e.g.:
xrandr –output LVDS –mode 1680×1050
repeat (2)…(4) several times, and hopefully the flickering stops …

Of course, this is NOT a real solution; I'm still hoping for a kernel/driver fix …

Best Answer