Cycling windowed / full-screen hangs X desktop on Raspberry Pi

[MV10]

Consistent, reproducible hang on the Raspberry Pi.

Running .NET 6, OpenTK 4.7.7 and 32-bit Raspbian Bullseye -- minimal repro code below just clears the screen and toggles back and forth between WindowState.Normal and WindowState.Fullscreen on spacebar keypresses. Sometimes I can get through two cycles (windowed, full, windowed, full), other times only one cycle. After that X is unresponsive, although the mouse works and I can connect over SSH. I ran pidof and found the PID for my test program and killed that, but X remains unresponsive. I have to reboot over SSH.

Since the GLFW redist doesn't include arm32 / armhf libraries, originally I was building GLFW locally according to advice from 2021 on the Pi forums. However, I also uninstalled that and ran the sudo apt install libglfw3 version, and both seem to behave identically. (And I see no indication there is anything wrong running the APT version, maybe they addressed it in the Bullseye release.)

Microsoft followed up on my VS bug report and found a work-around allowing remote-debug over SSH (their script incorrectly downloads the 64-bit debug client), so now I'm able to run a debug build of OpenTK if somebody wants me to look for anything in particular.

Minimal repro:

internal class Program
{
    static void Main(string[] args)
    {
        var gameCfg = new GameWindowSettings();
        
        var nativeCfg = new NativeWindowSettings
        {
            Title = "Test",
            Size = (960, 540),
            API = ContextAPI.OpenGLES,
            APIVersion = new Version(3, 2),
            Profile = ContextProfile.Core,
        };

        var win = new BugWindow(gameCfg, nativeCfg);
        win.Focus();
        win.Run();
        win.Dispose();
    }
}

public class BugWindow : GameWindow
{
    public BugWindow(GameWindowSettings gameSettings, NativeWindowSettings nativeSettings)
        : base(gameSettings, nativeSettings)
    { }

    protected override void OnLoad()
    {
        base.OnLoad();
        GL.ClearColor(0f, 0f, 1f, 1f);
    }

    protected override void OnRenderFrame(FrameEventArgs args)
    {
        base.OnRenderFrame(args);
        GL.Clear(ClearBufferMask.ColorBufferBit);
        Context.SwapBuffers();
    }

    protected override void OnResize(ResizeEventArgs e)
    {
        base.OnResize(e);
        GL.Viewport(0, 0, e.Width, e.Height);
    }

    protected override void OnUpdateFrame(FrameEventArgs e)
    {
        base.OnUpdateFrame(e);

        var input = KeyboardState;

        if (input.IsKeyReleased(Keys.Escape))
        {
            Close();
            return;
        }

        if (input.IsKeyReleased(Keys.Space))
        {
            WindowState = (WindowState == WindowState.Fullscreen) ? WindowState.Normal : WindowState.Fullscreen;
        }
    }
}