From 64c1bf890e04385b601c516132346e4da12e8ef8 Mon Sep 17 00:00:00 2001
From: Nikita Tsukanov <keks9n@gmail.com>
Date: Sun, 11 Oct 2020 15:55:21 +0300
Subject: [PATCH] Fixed DRM output

---
 src/Avalonia.OpenGL/Egl/EglContext.cs         |  3 ++-
 src/Avalonia.OpenGL/Egl/EglDisplay.cs         | 22 ++++++++++++-------
 .../Output/DrmOutput.cs                       | 12 +---------
 3 files changed, 17 insertions(+), 20 deletions(-)

diff --git a/src/Avalonia.OpenGL/Egl/EglContext.cs b/src/Avalonia.OpenGL/Egl/EglContext.cs
index 5365354418..249b4d547f 100644
--- a/src/Avalonia.OpenGL/Egl/EglContext.cs
+++ b/src/Avalonia.OpenGL/Egl/EglContext.cs
@@ -73,7 +73,8 @@ namespace Avalonia.OpenGL.Egl
                 var old = new RestoreContext(_egl, _disp.Handle, _lock);
                 var surf = surface ?? OffscreenSurface;
                 _egl.MakeCurrent(_disp.Handle, IntPtr.Zero, IntPtr.Zero, IntPtr.Zero);
-                if (!_egl.MakeCurrent(_disp.Handle, surf.DangerousGetHandle(), surf.DangerousGetHandle(), Context))
+                if (!_egl.MakeCurrent(_disp.Handle, surf?.DangerousGetHandle() ?? IntPtr.Zero,
+                    surf?.DangerousGetHandle() ?? IntPtr.Zero, Context))
                     throw OpenGlException.GetFormattedException("eglMakeCurrent", _egl);
                 success = true;
                 return old;
diff --git a/src/Avalonia.OpenGL/Egl/EglDisplay.cs b/src/Avalonia.OpenGL/Egl/EglDisplay.cs
index fd3de854f5..623364866b 100644
--- a/src/Avalonia.OpenGL/Egl/EglDisplay.cs
+++ b/src/Avalonia.OpenGL/Egl/EglDisplay.cs
@@ -158,15 +158,21 @@ namespace Avalonia.OpenGL.Egl
             var ctx = _egl.CreateContext(_display, _config, shareCtx?.Context ?? IntPtr.Zero, _contextAttributes);
             if (ctx == IntPtr.Zero)
                 throw OpenGlException.GetFormattedException("eglCreateContext", _egl);
-            var surf = _egl.CreatePBufferSurface(_display, _config, new[]
+            
+            var extensions = _egl.QueryString(Handle, EGL_EXTENSIONS);
+            
+            IntPtr surf = IntPtr.Zero;
+            if (extensions?.Contains("EGL_KHR_surfaceless_context") != true)
             {
-                EGL_WIDTH, 1,
-                EGL_HEIGHT, 1,
-                EGL_NONE
-            });
-            if (surf == IntPtr.Zero)
-                throw OpenGlException.GetFormattedException("eglCreatePBufferSurface", _egl);
-            var rv = new EglContext(this, _egl, shareCtx, ctx, context => new EglSurface(this, context, surf),
+                surf = _egl.CreatePBufferSurface(_display, _config,
+                    new[] { EGL_WIDTH, 1, EGL_HEIGHT, 1, EGL_NONE });
+                if (surf == IntPtr.Zero)
+                    throw OpenGlException.GetFormattedException("eglCreatePBufferSurface", _egl);
+            }
+
+            var rv = new EglContext(this, _egl, shareCtx, ctx,
+                context =>
+                    surf == IntPtr.Zero ? null : new EglSurface(this, context, surf),
                 _version, _sampleCount, _stencilSize);
             return rv;
         }
diff --git a/src/Linux/Avalonia.LinuxFramebuffer/Output/DrmOutput.cs b/src/Linux/Avalonia.LinuxFramebuffer/Output/DrmOutput.cs
index 72eed9e543..dc44d2d55f 100644
--- a/src/Linux/Avalonia.LinuxFramebuffer/Output/DrmOutput.cs
+++ b/src/Linux/Avalonia.LinuxFramebuffer/Output/DrmOutput.cs
@@ -141,17 +141,7 @@ namespace Avalonia.LinuxFramebuffer.Output
             _platformGl = new EglPlatformOpenGlInterface(_eglDisplay);
             _eglSurface =  _platformGl.CreateWindowSurface(_gbmTargetSurface);
 
-
-            EglContext CreateContext(EglContext share)
-            {
-                var offSurf = gbm_surface_create(device, 1, 1, GbmColorFormats.GBM_FORMAT_XRGB8888,
-                    GbmBoFlags.GBM_BO_USE_RENDERING);
-                if (offSurf == null)
-                    throw new InvalidOperationException("Unable to create 1x1 sized GBM surface");
-                return _eglDisplay.CreateContext(share, _platformGl.CreateWindowSurface(offSurf));
-            }
-            
-            _deferredContext = CreateContext(null);
+            _deferredContext = _platformGl.PrimaryEglContext;
 
             using (_deferredContext.MakeCurrent(_eglSurface))
             {