wsi/x11: Treat IMMEDIATE present mode the same as MAILBOX for Xwayland
As described in the second to last commit, sending buffers to the Wayland compositor as quickly as possible effectively results in mailbox behaviour.
Also, doing the same as for MAILBOX
present mode provides the following
benefits:
-
We use more images in the swapchain, which avoids stalls on the client side if the Wayland compositor directly uses the client buffers for scanout.
-
We wait for fences to signal before submitting a new buffer, which avoids missing frames in the Wayland compositor due to fences not signalling in time for a flip.
Closes: #3673 (closed)
/cc @bnieuwenhuizen