RFR: 8210547: [Linux] Uncontrolled framerate

Sat Oct 4 14:14:02 UTC 2025

On Sat, 4 Oct 2025 13:38:47 GMT, Thiago Milczarek Sayao <tsayao at openjdk.org> wrote:

> As Michael Zucchi pointed out on the mailing list, the high framerate occurs because `glXSwapBuffers() `operates asynchronously. To ensure proper synchronization, you can call `glFinish() `afterward, which blocks until the buffer swap is fully completed. However, when using `glXSwapIntervalSGI`, the swap interval setting applies globally rather than per drawable. In contrast, `glXSwapIntervalEXT` provides per-drawable control, allowing finer-grained vsync behavior.
> 
> I don't know if there are scenarios when the unlimited frame rate is needed - if so we should provide a option.
> 
> It also selects the correct visual for transparency which needs to be depth = 32 for X11.

Reviewers: @kevinrushforth @lukostyra

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PR Comment: https://git.openjdk.org/jfx/pull/1929#issuecomment-3368287755