Comment 11 for bug 1791312

I tried the glamor / tearfree - advice, but: with NO success; still flickering.
And, btw.: I don't think the flickering is an Xorg-issue;
it starts in "textmode" (!!) as soon as the radeon-kernel-driver loads. I think the kernel-driver
does NOT read Xorg-configurations.

Just for fun, I've tested different systems:
System kernel radeon.ko result
UBUNTU-14.04.5 3.13.0-164 2.36.0 O.K
puppy_slacko-6.3.2 3.14.55 2.37.0 O.K.
UBCD 3.16.0 2.39.0 FLICKER
UBUNTU 14.04.5 4.4.0-133 2.43.0 FLICKER
UBUNTU 18.04.1 4.15.0-42 2.50.0 FLICKER

So, I think the problem starts with a modification made in radeon.ko version 2.37.0 --> 2.39.0

Additionally I found a "kind of work-around": switch the mode several times!
thus:
- ignore flickering; start grafic mode
- xrandr --output LVDS --mode 1440x900; sleep 2; xrandr --output LVDS --mode 1680x1050;
- try that 2 ... 5 times until flickering stops!