[Bug 57442] Several applications: abnormal input delay with Wine

[WineHQ Bugzilla]

https://bugs.winehq.org/show_bug.cgi?id=57442

William Horvath  changed:

What    |Removed                     |Added
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                 CC|                            |[e-mail]

--- Comment #1 from William Horvath  ---
Regression commit:
54ca1ab607d3ff22a1f57a9561430f64c75f0916 "win32u: Simplify the logic for driver
messages polling."

I noticed this issue from a PeekMessage event loop like this:

while (running)
    {
        while (PeekMessage(&msg, NULL, 0, 0, PM_REMOVE))
        {
            if (msg.message == WM_QUIT) { running = false; break; }
            TranslateMessage(&msg);
            DispatchMessage(&msg);
        }
        if (running)
        {
            QueryPerformanceCounter(&current_time);
            double elapsed = get_ms_delta(last_check, current_time);
            if (elapsed >= 0.1) /* 10kHz */
            {
                process_key_state_changes();
                last_check = current_time;
            }
            Sleep(0);
        }
    }

If driver events (e.g. mouse motion, keypresses) are sent at a freq. greater
than 1000hz, the processing loop above only receives them in ~10ms intervals on
average, because most seem to be entirely dropped. If the events are sent at a
freq. less than or equal to 1000hz, then there's barely any added delay
(~0.1ms), and all of them are received, same as before the regression commit.

I only tested with `GetKeyboardState` + an external program sending X11 key
events at a constant rate, but reverting the mentioned commit allows even
0.25ms keypress intervals (8000hz) to all be received with minimal delay.