BTW, despite any appearances to the contrary, I recognize (and look forward to!) the superiority of an architecture based on fixed rate interrupts rather than a freewheel unsynchronized protocol. I was just afraid, previously, that:
1) All my stuff is gonna break! (Consider I've been using the same setup unchanged since the mid 2000s, and it's got a lot of self written code)
2) I'm gonna be stuck with a system I consider ugly!
3) My stuff breaking will be in exchange for nothing I consider worthwhile in return!
Now that I read the great article https://www.phoronix.com/scan.php?page=article&item=x_waylan..., much of my FUD has melted away. I know that #2 and #3 aren't true, #1 is probably true but now I'm looking forward to it.
Again, factually false. X has various synchronization options from the older double buffer protocol to the XSync extension to the GLX/DRI vsync commands.
I've also never seen tearing in X since like 2006.
Meanwhile, if you plumb atomic page flipping through the whole system and make it mandatory, the chances of having tearing are pretty nonexistent. But you have to drop legacy stuff from X if you want to do that.