Hi, Uwe reported that with a newest release of xserver-xorg-core, the bug disappeared. [1]
There has been new uploads recently in Stretch and Sid, which now have 2:1.19.2-1 and 2:1.19.3-1 respectively. Is one of this versions the one supposed to have "fixed" the bug? Could be helpfull if someone (lelutin?) gives a try back with the newest modsetting driver so that we know if it eventually works. bert. [1] https://bugs.freedesktop.org/show_bug.cgi?id=98742#c14