okay, i added it to /etc/X11/xorg.conf.t194_ref, see below.
In /var/log/Xorg.0.log is one line about it:
[ 10.999] (**) NVIDIA(0): Option “ForceFullCompositionPipeline” “on”
The problem persists.
# Copyright © 2017, NVIDIA CORPORATION. All Rights Reserved.
#
# This is the minimal configuration necessary to use the Tegra driver.
# Please refer to the xorg.conf man page for more configuration
# options provided by the X server, including display-related options
# provided by RandR 1.2 and higher.
# Disable extensions not useful on Tegra.
Section “Module”
Disable “dri”
SubSection “extmod”
Option “omit xfree86-dga”
EndSubSection
EndSection
Section “Device”
Identifier “Tegra0”
Driver “nvidia”
Option “AllowEmptyInitialConfiguration” “true”
Option “ForceFullCompositionPipeline” “on”
EndSection