if disabling GLX_EXT_buffer_age usage "fixed" it on at least one system, but not on the other(s) the problem *cannot* be the same on all

Please, still check whether you'r using glamor acceleration:

Code: Select all

grep -i glamor /var/log/Xorg.0.log

See eg. https://wiki.archlinux.org/index.php/ATI#Configuration on how to switch to EXA for testing, in case.

In my case (intel) only using LIBGL_DRI3_DISABLE=1 fixed the repaint issues.

using openbox solved the problem on th last pc..

"Surprise" - using a non compositing WM that does not make any use of your OpenGL driver bypasses GL related issues. Who would have thought that?

I bet your right arm that suspending the KWin compositor (SHift+Alt+F12) and your left arm that using xrender compositing in KWin will "solve" it as well.

That however does not add the least information to the topic nor your actuall (probably GL driver related) issue.

You've still not checked whether you're using GLAMOR acceleration, have you?

At least on my case I can tell I'm (on Intel) using SNA, and not GLAMOR.

EDIT: with the latest Mesa & Intel code and kernel 3.19 rc1 at least I no longer need LIBGL_DRI3_DISABLE set for KWin to behave.