https://bugs.kde.org/show_bug.cgi?id=450914
--- Comment #8 from Erik Kurzinger <ekurzin...@nvidia.com> --- Tried this with a debug NVIDIA driver, and it looks like the application is spending most of its time waiting for the PresentIdleNotify event from Xwayland. If vsync is disabled this should get delivered pretty much immediately, and as Samuel said, for windowed applications it does, but for full-screen applications for some reason we're only getting one every vblank interval. Probably the important different there is that Xwayland will use the "copy" path in xwayland-present.c for windowed applications but will use the "flip" path for full-screen / borderless applications. So like in the former case Xwayland will copy from the application's buffer to one of it's own buffers, and in the latter case it will pass the application's buffer directly to Kwin. As I understand it, with the copy path, the idle notification is sent immediately after the copy completes, but with the flip path it's only sent after the buffer has been released by Kwin. Is there possibly a difference between NVIDIA and Mesa that could cause Kwin to delay releasing these buffers? There is one known bug in our DRM driver where we don't report the correct timestamp for page flips (it will just be 0), not sure if that could be relevant. -- You are receiving this mail because: You are watching all bug changes.
