Good news: I succeeded with commenting out SDL code that deals with keyboard, and after that I was able to run pygame framebuffer graphics without root rights! But there is a small issue: there is a text cursor blanking at the bottom of the screen.
By the way, it turned out that /dev/console rights change mentioned in reply to the How do I let an SDL app (not running as root) use the console <https://unix.stackexchange.com/questions/58961/how-do-i-let-an-sdl-app-not-running-as-root-use-the-console> StackExchange post is not necessary, at least on Raspbian. My next steps are to run pygame framebuffer graphics as a daemon. I will try using systemd as a daemon supervisor, because this is the default choice in Raspbian. Kind regards, Roman Mescheryakov
