@AlwinLubSorry for replying a year late to your post. But honestly you are a lifesaver, I was trying to fix the same issue for a week, until I finally found your post. Thank you a ton for that.
I have questions though. Disabling multisampling does fix the issue when the app is a window in X11, but when writing directly to screen using SDL2 the whole image is scrambled.
Improvement compared to a black screen, but still not great. Did you find a way to write directly to screen without artifacts?
If not what display server you had the best results with, Weston or X11? Did touch work with it, touch doesn't work for me on X11
