[destructionator]

> X is still fundamentally an unsychronized protocol

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.

[md8z]

No, it's not factually false, those fall in the "pile of hacks" I mentioned, and none of them work in all cases, some of them are highly dependent on driver support which is spotty. I can show you various bug reports from the last few years of people still complaining about tearing. This problem is not even remotely close to being solved in X and I don't think it ever will be. Again just look at the bug reports.

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.