Use more aggressive xlib locking following the advice of the multithreaded X manpages (needs work).

Source/OpenTK/Platform/X11/API.cs

@@ -1,4 +1,4 @@
-#region --- License ---
+#region --- License ---
 /* Copyright (c) 2006, 2007 Stefanos Apostolopoulos
  * Contributions from Erik Ylvisaker
  * See license.txt for license info
@@ -1589,6 +1589,23 @@ XF86VidModeGetGammaRampSize(
         }
     }
     */
+
+    struct XLock : IDisposable
+    {
+        readonly IntPtr Display;
+
+        public XLock(IntPtr display)
+            : this()
+        {
+            Functions.XLockDisplay(display);
+            Display = display;
+        }
+
+        public void Dispose()
+        {
+            Functions.XUnlockDisplay(Display);
+        }
+    }
 }
 
 #pragma warning restore 3019

Source/OpenTK/Platform/X11/Functions.cs

@@ -1,4 +1,4 @@
-#region --- License ---
+#region --- License ---
 /* Licensed under the MIT/X11 license.
  * Copyright (c) 2006-2008 the OpenTK Team.
  * This notice may not be removed from any source distribution.
@@ -77,10 +77,18 @@ namespace OpenTK.Platform.X11
 
     internal static partial class Functions
     {
-        public static readonly object Lock = new object();
+        public static readonly object Lock = API.Lock;
 
         [DllImport("libX11", EntryPoint = "XOpenDisplay")]
-        public extern static IntPtr XOpenDisplay(IntPtr display);
+        extern static IntPtr sys_XOpenDisplay(IntPtr display);
+        public static IntPtr XOpenDisplay(IntPtr display)
+        {
+            lock (Lock)
+            {
+                return sys_XOpenDisplay(display);
+            }
+        }
+
         [DllImport("libX11", EntryPoint = "XCloseDisplay")]
         public extern static int XCloseDisplay(IntPtr display);
         [DllImport("libX11", EntryPoint = "XSynchronize")]

Source/OpenTK/Platform/X11/X11GLContext.cs

@@ -130,10 +130,13 @@ namespace OpenTK.Platform.X11
                         else
                             Debug.WriteLine("success!");
                         
+                        using (new XLock(Display))
+                        {
                             Functions.XFree((IntPtr)fbconfigs);
                         }
                     }
                 }
+            }
             
             if (Handle == ContextHandle.Zero)
             {

Source/OpenTK/Platform/X11/X11GLNative.cs

@@ -122,7 +122,7 @@ namespace OpenTK.Platform.X11
 
             Debug.Indent();
             
-            lock (API.Lock)
+            using (new XLock(window.Display))
             {
                 if (!mode.Index.HasValue)
                     throw new GraphicsModeException("Invalid or unsupported GraphicsMode.");
@@ -164,7 +164,7 @@ namespace OpenTK.Platform.X11
             hints.base_width = width;
             hints.base_height = height;
             hints.flags = (IntPtr)(XSizeHintsFlags.PSize | XSizeHintsFlags.PPosition);
-            lock (API.Lock)
+            using (new XLock(window.Display))
             {
                 Functions.XSetWMNormalHints(window.Display, window.WindowHandle, ref hints);
 
@@ -194,20 +194,17 @@ namespace OpenTK.Platform.X11
                 Debug.Indent();
 
                 // Open a display connection to the X server, and obtain the screen and root window.
-                window.Display = API.DefaultDisplay;
+                window.Display = Functions.XOpenDisplay(IntPtr.Zero);
+                //window.Display = API.DefaultDisplay;
                 if (window.Display == IntPtr.Zero)
                     throw new Exception("Could not open connection to X");
 
-                try
+                using (new XLock(window.Display))
                 {
                     Functions.XLockDisplay(window.Display);
                     window.Screen = Functions.XDefaultScreen(window.Display); //API.DefaultScreen;
                     window.RootWindow = Functions.XRootWindow(window.Display, window.Screen); // API.RootWindow;
                 }
-                finally
-                {
-                    Functions.XUnlockDisplay(window.Display);
-                }
 
                 Debug.Print("Display: {0}, Screen {1}, Root window: {2}", window.Display, window.Screen,
                             window.RootWindow);
@@ -231,6 +228,8 @@ namespace OpenTK.Platform.X11
         /// Registers the necessary atoms for GameWindow.
         /// </summary>
         private void RegisterAtoms(X11WindowInfo window)
+        {
+            using (new XLock(window.Display))
             {
                 Debug.WriteLine("Registering atoms.");
                 _atom_wm_destroy = Functions.XInternAtom(window.Display, "WM_DELETE_WINDOW", true);
@@ -267,6 +266,7 @@ namespace OpenTK.Platform.X11
 //            //WMTitle = atoms[offset++];
 //            //UTF8String = atoms[offset++];
             }
+        }
 
         #endregion
 

Source/OpenTK/Platform/X11/X11GraphicsMode.cs

@@ -1,4 +1,4 @@
-#region --- License ---
+#region --- License ---
 /* Licensed under the MIT/X11 license.
  * Copyright (c) 2006-2008 the OpenTK Team.
  * This notice may not be removed from any source distribution.
@@ -35,7 +35,8 @@ namespace OpenTK.Platform.X11
         public GraphicsMode SelectGraphicsMode(ColorFormat color, int depth, int stencil, int samples, ColorFormat accum,
                                                int buffers, bool stereo)
         {
-            GraphicsMode gfx;                               // The actual GraphicsMode that will be selected.
+            GraphicsMode gfx;
+            // The actual GraphicsMode that will be selected.
             IntPtr visual = IntPtr.Zero;
             IntPtr display = API.DefaultDisplay;
             
@@ -66,7 +67,8 @@ namespace OpenTK.Platform.X11
             Glx.GetConfig(display, ref info, GLXAttribute.STENCIL_SIZE, out stencil);
             Glx.GetConfig(display, ref info, GLXAttribute.SAMPLES, out samples);
             Glx.GetConfig(display, ref info, GLXAttribute.DOUBLEBUFFER, out buffers);
-            ++buffers;  // the above lines returns 0 - false and 1 - true.
+            ++buffers;
+            // the above lines returns 0 - false and 1 - true.
             int st;
             Glx.GetConfig(display, ref info, GLXAttribute.STEREO, out st);
             stereo = st != 0;
@@ -74,7 +76,10 @@ namespace OpenTK.Platform.X11
             gfx = new GraphicsMode(info.VisualID, new ColorFormat(r, g, b, a), depth, stencil, samples,
             new ColorFormat(ar, ag, ab, aa), buffers, stereo);
             
+            using (new XLock(display))
+            {
                 Functions.XFree(visual);
+            }
             
             return gfx;
         }

Source/OpenTK/Platform/X11/X11Input.cs

@@ -1,4 +1,4 @@
-#region --- License ---
+#region --- License ---
 /* Copyright (c) 2006, 2007 Stefanos Apostolopoulos
  * See license.txt for license info
  */
@@ -61,6 +61,8 @@ namespace OpenTK.Platform.X11
             mouse.NumberOfWheels = 1;
             dummy_mice_list.Add(mouse);
             
+            using (new XLock(window.Display))
+            {
                 // Init keyboard
                 API.DisplayKeycodes(window.Display, ref firstKeyCode, ref lastKeyCode);
                 Debug.Print("First keycode: {0}, last {1}", firstKeyCode, lastKeyCode);
@@ -85,6 +87,7 @@ namespace OpenTK.Platform.X11
                 // be reset before the program exits.
                 bool supported;
                 Functions.XkbSetDetectableAutoRepeat(window.Display, true, out supported);
+            }
 
             Debug.Unindent();
         }

Source/OpenTK/Platform/X11/X11XrandrDisplayDevice.cs

@@ -1,4 +1,4 @@
-#region --- License ---
+#region --- License ---
 /* Licensed under the MIT/X11 license.
  * Copyright (c) 2006-2008 the OpenTK Team.
  * This notice may not be removed from any source distribution.
@@ -42,7 +42,10 @@ namespace OpenTK.Platform.X11
             for (int screen = 0; screen < API.ScreenCount; screen++)
             {
                 IntPtr timestamp_of_last_update;
+                using (new XLock(API.DefaultDisplay))
+                {
                     Functions.XRRTimes(API.DefaultDisplay, screen, out timestamp_of_last_update);
+                }
                 lastConfigUpdate.Add(timestamp_of_last_update);
                 
                 List<DisplayResolution> available_res = new List<DisplayResolution>();
@@ -60,7 +63,11 @@ namespace OpenTK.Platform.X11
                         Debug.Print("[Warning] XRandR returned an invalid resolution ({0}) for display device {1}", size, screen);
                         continue;
                     }
-                    short[] rates = Functions.XRRRates(API.DefaultDisplay, screen, resolution_count);
+                    short[] rates = null;
+                    using (new XLock(API.DefaultDisplay))
+                    {
+                        rates = Functions.XRRRates(API.DefaultDisplay, screen, resolution_count);
+                    }
 
                     // It seems that XRRRates returns 0 for modes that are larger than the screen
                     // can support, as well as for all supported modes. On Ubuntu 7.10 the tool
@@ -113,9 +120,12 @@ namespace OpenTK.Platform.X11
         #region static int[] FindAvailableDepths(int screen)
 
         static int[] FindAvailableDepths(int screen)
+        {
+            using (new XLock(API.DefaultDisplay))
             {
                 return Functions.XListDepths(API.DefaultDisplay, screen);
             }
+        }
 
         #endregion
 
@@ -123,7 +133,11 @@ namespace OpenTK.Platform.X11
 
         static XRRScreenSize[] FindAvailableResolutions(int screen)
         {
-            XRRScreenSize[] resolutions = Functions.XRRSizes(API.DefaultDisplay, screen);
+            XRRScreenSize[] resolutions = null;
+            using (new XLock(API.DefaultDisplay))
+            {
+                resolutions = Functions.XRRSizes(API.DefaultDisplay, screen);
+            }
             if (resolutions == null)
                 throw new NotSupportedException("XRandR extensions not available.");
             return resolutions;
@@ -134,13 +148,16 @@ namespace OpenTK.Platform.X11
         #region static float FindCurrentRefreshRate(int screen)
 
         static float FindCurrentRefreshRate(int screen)
+        {
+            short rate = 0;
+            using (new XLock(API.DefaultDisplay))
             {
                 IntPtr screen_config = Functions.XRRGetScreenInfo(API.DefaultDisplay, Functions.XRootWindow(API.DefaultDisplay, screen));
                 ushort rotation = 0;
                 int size = Functions.XRRConfigCurrentConfiguration(screen_config, out rotation);
-            short rate = Functions.XRRConfigCurrentRate(screen_config);
+                rate = Functions.XRRConfigCurrentRate(screen_config);
                 Functions.XRRFreeScreenConfigInfo(screen_config);
-
+            }
             return (float)rate;
         }
 
@@ -149,9 +166,12 @@ namespace OpenTK.Platform.X11
         #region private static int FindCurrentDepth(int screen)
 
         private static int FindCurrentDepth(int screen)
+        {
+            using (new XLock(API.DefaultDisplay))
             {
                 return (int)Functions.XDefaultDepth(API.DefaultDisplay, screen);
             }
+        }
 
         #endregion
 
@@ -163,6 +183,8 @@ namespace OpenTK.Platform.X11
         {
             // If resolution == null, restore to default resolution (new_resolution_index = 0).
 
+            using (new XLock(API.DefaultDisplay))
+            {
                 int screen = deviceToScreen[device];
                 IntPtr root = Functions.XRootWindow(API.DefaultDisplay, screen);
                 IntPtr screen_config = Functions.XRRGetScreenInfo(API.DefaultDisplay, root);
@@ -182,6 +204,7 @@ namespace OpenTK.Platform.X11
                 return 0 == Functions.XRRSetScreenConfigAndRate(API.DefaultDisplay, screen_config, root, new_resolution_index,
                     current_rotation, (short)(resolution != null ? resolution.RefreshRate : 0), lastConfigUpdate[screen]);
             }
+        }
 
         public bool TryRestoreResolution(DisplayDevice device)
         {