Frame callback not sent for Xwayland fullscreen windows sometimes
Affected version
mutter Wayland 3.38 or newer
Bug summary
Under some circumstances, Xwayland never receives a frame callback for a fullscreen window. If "vsync" is enabled in the client, this results in 1 fps, since only Xwayland's 1 Hz fallback timer keeps the client updating.
Steps to reproduce
- Start the Steam client
- Enter Big Picture mode.
- In about 1 out of 10 cases, the Big Picture UI will exhibit the problem.
Workarounds
- Alt-Tab and go back to the affected fullscreen window (no need to switch to another window first)
- Alt-F2. As soon as the dialogue is visible (and even after it's closed again), the fullscreen client runs normally, which means Xwayland must have finally received the frame callback (and keeps receiving new ones).
Edited by Michel Dänzer