Comment 2 for bug 1728069

The log message at least, means the compositor has released the buffer too early (before compositing). Hence the client will appear to hang as new frames don't reach the screen.

Actually historically Mir holds buffers for even longer than that to deal with multi-monitor frame sync. But if you only have a single monitor then you can release the buffer back to the client as soon as eglSwapBuffers has returned for the compositor.

We also toyed with something dubbed the "early release optimization" a while ago, which sounds like it might help Wayland. That's basically the same thing as assuming you only ever have one monitor to feed... It was disabled in r3441 though, due to it increasing lag in native Mir clients (possibly wouldn't hurt Wayland clients though if they are self-throttling with their own client-side vsync).